modifying lasers?

[peedonurpoptart]

how would one go about "modifying" an ordinary 5mW laser, green or red, to output a more powerful beam? I have heard things as simple as prying off the power switch and screwing a screw over a little, to things as complicated as taking the laser apart and adding lenses. Does anyone have any information on this?

[peedonurpoptart]

how would one go about "modifying" an ordinary 5mW laser, green or red, to output a more powerful beam? I have heard things as simple as prying off the power switch and screwing a screw over a little, to things as complicated as taking the laser apart and adding lenses. Does anyone have any information on this?

[peedonurpoptart]

how would one go about "modifying" an ordinary 5mW laser, green or red, to output a more powerful beam? I have heard things as simple as prying off the power switch and screwing a screw over a little, to things as complicated as taking the laser apart and adding lenses. Does anyone have any information on this?

[Arthis]

Using just a higher power input may rise a very little your beam.

But for a powerful beam you need to change the cristal (which is here doped glass) to a bigger one, have lenses that are more precise.

Don't dream you can't make a weapon with your pen.

[Arthis]

Using just a higher power input may rise a very little your beam.

But for a powerful beam you need to change the cristal (which is here doped glass) to a bigger one, have lenses that are more precise.

Don't dream you can't make a weapon with your pen.

[Arthis]

Using just a higher power input may rise a very little your beam.

But for a powerful beam you need to change the cristal (which is here doped glass) to a bigger one, have lenses that are more precise.

Don't dream you can't make a weapon with your pen.

[aikon]

Modifying a simple 5 mW handheld device is not an option, because it wouldn't last long. Go to http://www.laserglow.com/handheld.html
This company sells more powerful handheld laser devices, but they aren't cheap.

[aikon]

Modifying a simple 5 mW handheld device is not an option, because it wouldn't last long. Go to http://www.laserglow.com/handheld.html
This company sells more powerful handheld laser devices, but they aren't cheap.

[aikon]

Modifying a simple 5 mW handheld device is not an option, because it wouldn't last long. Go to http://www.laserglow.com/handheld.html
This company sells more powerful handheld laser devices, but they aren't cheap.

[akinrog]

If you want something more powerful then you may use the ordinary semiconductor lasers to pump larger ones.

As other members pointed out, I don't think increasing power input of a semiconductor shall do no good (due to heat up) to the laser neither it shall increase significantly its power output.

[akinrog]

If you want something more powerful then you may use the ordinary semiconductor lasers to pump larger ones.

As other members pointed out, I don't think increasing power input of a semiconductor shall do no good (due to heat up) to the laser neither it shall increase significantly its power output.

[akinrog]

If you want something more powerful then you may use the ordinary semiconductor lasers to pump larger ones.

As other members pointed out, I don't think increasing power input of a semiconductor shall do no good (due to heat up) to the laser neither it shall increase significantly its power output.

[grendel23]

I have a Leadlight green DPSS laser pointer which puts out 35mw. I replaced a resistor and adjusted a pot to get that output.
I also have an argon ion laser that will put out over 2 watts, once a put together a power supply that will supply 220 volts DC at 30A.

[grendel23]

I have a Leadlight green DPSS laser pointer which puts out 35mw. I replaced a resistor and adjusted a pot to get that output.
I also have an argon ion laser that will put out over 2 watts, once a put together a power supply that will supply 220 volts DC at 30A.

[grendel23]

I have a Leadlight green DPSS laser pointer which puts out 35mw. I replaced a resistor and adjusted a pot to get that output.
I also have an argon ion laser that will put out over 2 watts, once a put together a power supply that will supply 220 volts DC at 30A.

[Marvin]

What was the DPSS rated for when bought and how long are you expecting the pump laser to last at the new power level?

Ive heard about these but have no idea what they be pushed to before lifespan becomes very short.

[Marvin]

What was the DPSS rated for when bought and how long are you expecting the pump laser to last at the new power level?

Ive heard about these but have no idea what they be pushed to before lifespan becomes very short.

[Marvin]

What was the DPSS rated for when bought and how long are you expecting the pump laser to last at the new power level?

Ive heard about these but have no idea what they be pushed to before lifespan becomes very short.

[FUTI]

This is something I thought about but never had time to research. I asumed also that busting laser output will reduce lifetime, but I have a question. Can use of shorter pulses extend lifetime/counteract with expected overheating/degrading of laser? I want to modify one of those laser pointer pen so if anyone have some experience with that please send me a PM.

[FUTI]

This is something I thought about but never had time to research. I asumed also that busting laser output will reduce lifetime, but I have a question. Can use of shorter pulses extend lifetime/counteract with expected overheating/degrading of laser? I want to modify one of those laser pointer pen so if anyone have some experience with that please send me a PM.

[FUTI]

This is something I thought about but never had time to research. I asumed also that busting laser output will reduce lifetime, but I have a question. Can use of shorter pulses extend lifetime/counteract with expected overheating/degrading of laser? I want to modify one of those laser pointer pen so if anyone have some experience with that please send me a PM.

[James]

I don't suppose you could put a peltier cooler on the back to help it keep cool. Mybe a heatsink.

[James]

I don't suppose you could put a peltier cooler on the back to help it keep cool. Mybe a heatsink.

[James]

I don't suppose you could put a peltier cooler on the back to help it keep cool. Mybe a heatsink.

[malzraa]

Yeah, a regular laser diode would not increase output with input power, it would just fry.

[malzraa]

Yeah, a regular laser diode would not increase output with input power, it would just fry.

[malzraa]

Yeah, a regular laser diode would not increase output with input power, it would just fry.

[Jacks Complete]

LOL. Ok, time for some actual useful data for you guys.

There are two types of laser pen, currently. Red and green.

Red (whatever the actual frequency, it is normally from 670 to 635, duller to brighter) is directly from a semiconductor laser. Green is from an IR laser that passes through a doubler chip then an IR filter, and has the wavelength halved. These output at about 535nm.

The longer the wavelength, the easier it is to get a laser to lase. This means that IR is easier than red lasers are easier than green, and blue is not yet possible with a useable lifetime. UV is impossible. This is a fundamental law of physics - in "big" lasers, UV lasers are rare, and the x-ray lasers of starwars are still just dreams.

Anyway, there are various types of diode lasers in use. Most red diodes will not go above ten mW regardless of what you do. The green lasers aren't so fussy, as they are actually IR, and can be pumped harder (more current) without overheating the laseing junction, because it is (much) easier to get an IR photon than a red photon, and therefore the efficiency is higher.

So we take our green laser pen apart, and we tweak it. Now, most of the diodes are de-rated, since 5mW is the most considered safe. As with everything, however, there are a range of values. Some of the lasers are very efficient, and lase at the required power at 5% of the nominal current. Others require 50 or even 100% of the maximum rated current to get the right power output. Those that require 101% get tuned to a lower power, and get sold as 1mW laser pens.

Now, we take the pen, and we tune it such that the current (which is the limiting factor) is just a fraction below the maximum rating (being careful not to exceed the maximum gate voltage). We have to be very careful, since ESD will kill the bare diode instantly, as will a negative gate voltage or an overcurrent condition. This may increase the power by a few percent in some cases, or let you run it at nearly 50mW (like one of mine). It is, I think, a Normal distribution.

Sony make the best diodes, and these have the highest tuning potential, however, it is impossible to know before you try what your max power out will be.

Now, nothing comes for free. Higher current draw due to increased gate voltage means a (potentially much) shorter battery lifetime, and, due to the way laser diodes work, a reduced laser lifetime.

Diode lasers go down in power over their lifetime. One of my old red 670nm 5mW lasers is now barely visible. The damage mechanism is cumulative, and works as follows:

When power is applied, the lifetime of the junction is reduced by one half for every ten degrees C warmer it gets.

A laser with a lifetime of 100 hours at 0 (above ambient) drops to just 25 hours at 20 degrees C. Pumping the maximum current you can get away with through the gate means it gets pretty warm. You can feel that the pen I have gets warm to the touch, and, since the body of the pen is the aluminium heat sink, this is obviously dramatically reducing the diode lifetime. If it gets to 40 degrees, your lifetime is down to just 6 hours.

Stepping the power back down after a time will slow the damage rate, but the damage done is done - you don't get any time back - so after 5 hours at 40 degrees you have 1 hour left. Drop the power back so it runs cold again, and you have 1/6th of the lifetime at 0, which is 100 hours/6 = 16 hours left. As a typical example, a Sony CD laser runs at 70 degrees and outputs 25mW optical. The typical lifetime is 1000 hours.

Other main factors are: thermal shock (rare in a mounted diode) and physical shock (try not to drop it)

http://www.sony.net/Products/SC-HP/tec/catalog/pdf/laser_2.pdf gives lots of general detail about the Sony diodes. http://www.eio.com/repairfaq/sam/laserdio.htm is the Sam's LASER FAQ for semiconductor lasers - he's really good at this stuff, and there is tons of info.

As for laser safety, read up on it. Retina damage isn't funny. Yes, it's a cool light sabre, you can point at stars and mountains, but more than likely you will shine it through a window and hit your own eye with 10% of that beam, or hit a mirror then your face for 90%.

Yes, you can damage your eyes for a long time, even forever. And that's a very long time. Pull one on someone and they will get very pissed off, and they won't go blind for a few hours, probably, by which time you are in jail or stabbed/beaten to a pulp.

Possession of a wrongly labelled laser is an offence in the UK, so re-label yours. Use it like a dick and you will get arrested, same as if you waved a sword, a pen or a hammer around.

Powerful lasers are not toys, same as a rifle. A moments mistake because you were silly or just didn't know can last forever.

On a lighter note, you should see what a good Class 4 CO2 laser at 10.6 microns can do to a fire brick! Melting your name in to it is fun. Just be aware that the reflections from the brick will burn your eyes out in less time than it takes to blink, and, although you can make it about the size of a computer tower, you need 3 phase electric and a fast flowing water supply for cooling.

So not quite as portable.

[Jacks Complete]

LOL. Ok, time for some actual useful data for you guys.

There are two types of laser pen, currently. Red and green.

Red (whatever the actual frequency, it is normally from 670 to 635, duller to brighter) is directly from a semiconductor laser. Green is from an IR laser that passes through a doubler chip then an IR filter, and has the wavelength halved. These output at about 535nm.

The longer the wavelength, the easier it is to get a laser to lase. This means that IR is easier than red lasers are easier than green, and blue is not yet possible with a useable lifetime. UV is impossible. This is a fundamental law of physics - in "big" lasers, UV lasers are rare, and the x-ray lasers of starwars are still just dreams.

Anyway, there are various types of diode lasers in use. Most red diodes will not go above ten mW regardless of what you do. The green lasers aren't so fussy, as they are actually IR, and can be pumped harder (more current) without overheating the laseing junction, because it is (much) easier to get an IR photon than a red photon, and therefore the efficiency is higher.

So we take our green laser pen apart, and we tweak it. Now, most of the diodes are de-rated, since 5mW is the most considered safe. As with everything, however, there are a range of values. Some of the lasers are very efficient, and lase at the required power at 5% of the nominal current. Others require 50 or even 100% of the maximum rated current to get the right power output. Those that require 101% get tuned to a lower power, and get sold as 1mW laser pens.

Now, we take the pen, and we tune it such that the current (which is the limiting factor) is just a fraction below the maximum rating (being careful not to exceed the maximum gate voltage). We have to be very careful, since ESD will kill the bare diode instantly, as will a negative gate voltage or an overcurrent condition. This may increase the power by a few percent in some cases, or let you run it at nearly 50mW (like one of mine). It is, I think, a Normal distribution.

Sony make the best diodes, and these have the highest tuning potential, however, it is impossible to know before you try what your max power out will be.

Now, nothing comes for free. Higher current draw due to increased gate voltage means a (potentially much) shorter battery lifetime, and, due to the way laser diodes work, a reduced laser lifetime.

Diode lasers go down in power over their lifetime. One of my old red 670nm 5mW lasers is now barely visible. The damage mechanism is cumulative, and works as follows:

When power is applied, the lifetime of the junction is reduced by one half for every ten degrees C warmer it gets.

A laser with a lifetime of 100 hours at 0 (above ambient) drops to just 25 hours at 20 degrees C. Pumping the maximum current you can get away with through the gate means it gets pretty warm. You can feel that the pen I have gets warm to the touch, and, since the body of the pen is the aluminium heat sink, this is obviously dramatically reducing the diode lifetime. If it gets to 40 degrees, your lifetime is down to just 6 hours.

Stepping the power back down after a time will slow the damage rate, but the damage done is done - you don't get any time back - so after 5 hours at 40 degrees you have 1 hour left. Drop the power back so it runs cold again, and you have 1/6th of the lifetime at 0, which is 100 hours/6 = 16 hours left. As a typical example, a Sony CD laser runs at 70 degrees and outputs 25mW optical. The typical lifetime is 1000 hours.

Other main factors are: thermal shock (rare in a mounted diode) and physical shock (try not to drop it)

http://www.sony.net/Products/SC-HP/tec/catalog/pdf/laser_2.pdf gives lots of general detail about the Sony diodes. http://www.eio.com/repairfaq/sam/laserdio.htm is the Sam's LASER FAQ for semiconductor lasers - he's really good at this stuff, and there is tons of info.

As for laser safety, read up on it. Retina damage isn't funny. Yes, it's a cool light sabre, you can point at stars and mountains, but more than likely you will shine it through a window and hit your own eye with 10% of that beam, or hit a mirror then your face for 90%.

Yes, you can damage your eyes for a long time, even forever. And that's a very long time. Pull one on someone and they will get very pissed off, and they won't go blind for a few hours, probably, by which time you are in jail or stabbed/beaten to a pulp.

Possession of a wrongly labelled laser is an offence in the UK, so re-label yours. Use it like a dick and you will get arrested, same as if you waved a sword, a pen or a hammer around.

Powerful lasers are not toys, same as a rifle. A moments mistake because you were silly or just didn't know can last forever.

On a lighter note, you should see what a good Class 4 CO2 laser at 10.6 microns can do to a fire brick! Melting your name in to it is fun. Just be aware that the reflections from the brick will burn your eyes out in less time than it takes to blink, and, although you can make it about the size of a computer tower, you need 3 phase electric and a fast flowing water supply for cooling.

So not quite as portable.

[Jacks Complete]

LOL. Ok, time for some actual useful data for you guys.

There are two types of laser pen, currently. Red and green.

Red (whatever the actual frequency, it is normally from 670 to 635, duller to brighter) is directly from a semiconductor laser. Green is from an IR laser that passes through a doubler chip then an IR filter, and has the wavelength halved. These output at about 535nm.

The longer the wavelength, the easier it is to get a laser to lase. This means that IR is easier than red lasers are easier than green, and blue is not yet possible with a useable lifetime. UV is impossible. This is a fundamental law of physics - in "big" lasers, UV lasers are rare, and the x-ray lasers of starwars are still just dreams.

Anyway, there are various types of diode lasers in use. Most red diodes will not go above ten mW regardless of what you do. The green lasers aren't so fussy, as they are actually IR, and can be pumped harder (more current) without overheating the laseing junction, because it is (much) easier to get an IR photon than a red photon, and therefore the efficiency is higher.

So we take our green laser pen apart, and we tweak it. Now, most of the diodes are de-rated, since 5mW is the most considered safe. As with everything, however, there are a range of values. Some of the lasers are very efficient, and lase at the required power at 5% of the nominal current. Others require 50 or even 100% of the maximum rated current to get the right power output. Those that require 101% get tuned to a lower power, and get sold as 1mW laser pens.

Now, we take the pen, and we tune it such that the current (which is the limiting factor) is just a fraction below the maximum rating (being careful not to exceed the maximum gate voltage). We have to be very careful, since ESD will kill the bare diode instantly, as will a negative gate voltage or an overcurrent condition. This may increase the power by a few percent in some cases, or let you run it at nearly 50mW (like one of mine). It is, I think, a Normal distribution.

Sony make the best diodes, and these have the highest tuning potential, however, it is impossible to know before you try what your max power out will be.

Now, nothing comes for free. Higher current draw due to increased gate voltage means a (potentially much) shorter battery lifetime, and, due to the way laser diodes work, a reduced laser lifetime.

Diode lasers go down in power over their lifetime. One of my old red 670nm 5mW lasers is now barely visible. The damage mechanism is cumulative, and works as follows:

When power is applied, the lifetime of the junction is reduced by one half for every ten degrees C warmer it gets.

A laser with a lifetime of 100 hours at 0 (above ambient) drops to just 25 hours at 20 degrees C. Pumping the maximum current you can get away with through the gate means it gets pretty warm. You can feel that the pen I have gets warm to the touch, and, since the body of the pen is the aluminium heat sink, this is obviously dramatically reducing the diode lifetime. If it gets to 40 degrees, your lifetime is down to just 6 hours.

Stepping the power back down after a time will slow the damage rate, but the damage done is done - you don't get any time back - so after 5 hours at 40 degrees you have 1 hour left. Drop the power back so it runs cold again, and you have 1/6th of the lifetime at 0, which is 100 hours/6 = 16 hours left. As a typical example, a Sony CD laser runs at 70 degrees and outputs 25mW optical. The typical lifetime is 1000 hours.

Other main factors are: thermal shock (rare in a mounted diode) and physical shock (try not to drop it)

http://www.sony.net/Products/SC-HP/tec/catalog/pdf/laser_2.pdf gives lots of general detail about the Sony diodes. http://www.eio.com/repairfaq/sam/laserdio.htm is the Sam's LASER FAQ for semiconductor lasers - he's really good at this stuff, and there is tons of info.

As for laser safety, read up on it. Retina damage isn't funny. Yes, it's a cool light sabre, you can point at stars and mountains, but more than likely you will shine it through a window and hit your own eye with 10% of that beam, or hit a mirror then your face for 90%.

Yes, you can damage your eyes for a long time, even forever. And that's a very long time. Pull one on someone and they will get very pissed off, and they won't go blind for a few hours, probably, by which time you are in jail or stabbed/beaten to a pulp.

Possession of a wrongly labelled laser is an offence in the UK, so re-label yours. Use it like a dick and you will get arrested, same as if you waved a sword, a pen or a hammer around.

Powerful lasers are not toys, same as a rifle. A moments mistake because you were silly or just didn't know can last forever.

On a lighter note, you should see what a good Class 4 CO2 laser at 10.6 microns can do to a fire brick! Melting your name in to it is fun. Just be aware that the reflections from the brick will burn your eyes out in less time than it takes to blink, and, although you can make it about the size of a computer tower, you need 3 phase electric and a fast flowing water supply for cooling.

So not quite as portable.

[a_bab]

Just something to add:
-you can actually double the power of the red cheap pointer if you manage to insert an extra button cell (sam Lasers FAQ). That will fry the diode instantly is same cases though.
-there are yellow laser pointer available, at around 130 bucks. These are DPSS as the green ones.
A year ago there was a blue laser pointer on e-bay, for around 2000 bucks.
-there are violet (not UV!) diodes available, for 3000 dollars. They can be mounted in a pointer

In a matter on 5 years, when the blue ray DVD units will become obsolete, we'll have blue diodes for our pointers.

[a_bab]

Just something to add:
-you can actually double the power of the red cheap pointer if you manage to insert an extra button cell (sam Lasers FAQ). That will fry the diode instantly is same cases though.
-there are yellow laser pointer available, at around 130 bucks. These are DPSS as the green ones.
A year ago there was a blue laser pointer on e-bay, for around 2000 bucks.
-there are violet (not UV!) diodes available, for 3000 dollars. They can be mounted in a pointer

In a matter on 5 years, when the blue ray DVD units will become obsolete, we'll have blue diodes for our pointers.

[a_bab]

Just something to add:
-you can actually double the power of the red cheap pointer if you manage to insert an extra button cell (sam Lasers FAQ). That will fry the diode instantly is same cases though.
-there are yellow laser pointer available, at around 130 bucks. These are DPSS as the green ones.
A year ago there was a blue laser pointer on e-bay, for around 2000 bucks.
-there are violet (not UV!) diodes available, for 3000 dollars. They can be mounted in a pointer

In a matter on 5 years, when the blue ray DVD units will become obsolete, we'll have blue diodes for our pointers.

[grendel23]

My green pointer came from the factory rated at 5mw, the most that can be legally sold in the US; it pulled 280ma and actually put out about 15mw. From what I have read, my unit is better than most. I bumped the current to 380ma which is just over the rating of the diode which is 375ma, so diode life should be acceptable. At that current, power is between 25 and 35mw depending on the temperature. Some people are running 550-600ma and getting 100+mw, but diode and crystal life will be greatly reduced.

[grendel23]

My green pointer came from the factory rated at 5mw, the most that can be legally sold in the US; it pulled 280ma and actually put out about 15mw. From what I have read, my unit is better than most. I bumped the current to 380ma which is just over the rating of the diode which is 375ma, so diode life should be acceptable. At that current, power is between 25 and 35mw depending on the temperature. Some people are running 550-600ma and getting 100+mw, but diode and crystal life will be greatly reduced.

[grendel23]

My green pointer came from the factory rated at 5mw, the most that can be legally sold in the US; it pulled 280ma and actually put out about 15mw. From what I have read, my unit is better than most. I bumped the current to 380ma which is just over the rating of the diode which is 375ma, so diode life should be acceptable. At that current, power is between 25 and 35mw depending on the temperature. Some people are running 550-600ma and getting 100+mw, but diode and crystal life will be greatly reduced.

[FUTI]

to Jack's Complete: Thanks for the usefull data. But when I asked about heating of the laser diode in modified pointer pen I hoped that heating can be reduced by implementing a small circuitry in place of switch that will allow you to form a time frequency tunable laser pulses (not wavelength of ligth but rather use of short flashes). I hoped that this will make heat disipation better compared to continuous work of laser pointer pen. I'm also gratefull for other solutions proposed by other members regarding cooling of device. Is there something wrong in my logic? If we can't make pointer to work in flashes (altough I don't see the reason why this wouldn't work) maybe we can alter it in other way to modulate the current given to diode so it produce peak power as maximum and normal/declared power as minumum of power output in some time frequency domain. I'm almost certain that I saw declaration on one of the pointers I had saying it has wavelength 560nm and 50mW output but I will go and buy new one to make sure tomorrow. Heating by electromagnetic radiation, and normal cooling through heat sink (conduction) and/or air cooling (convection) are different enough to make me confused is cooling of this laser device (as handheld version) posible. I wouldn't expect anyway that busting of power is remarkable as the optics usually isn't made to withstand that kind of molestation.

[FUTI]

to Jack's Complete: Thanks for the usefull data. But when I asked about heating of the laser diode in modified pointer pen I hoped that heating can be reduced by implementing a small circuitry in place of switch that will allow you to form a time frequency tunable laser pulses (not wavelength of ligth but rather use of short flashes). I hoped that this will make heat disipation better compared to continuous work of laser pointer pen. I'm also gratefull for other solutions proposed by other members regarding cooling of device. Is there something wrong in my logic? If we can't make pointer to work in flashes (altough I don't see the reason why this wouldn't work) maybe we can alter it in other way to modulate the current given to diode so it produce peak power as maximum and normal/declared power as minumum of power output in some time frequency domain. I'm almost certain that I saw declaration on one of the pointers I had saying it has wavelength 560nm and 50mW output but I will go and buy new one to make sure tomorrow. Heating by electromagnetic radiation, and normal cooling through heat sink (conduction) and/or air cooling (convection) are different enough to make me confused is cooling of this laser device (as handheld version) posible. I wouldn't expect anyway that busting of power is remarkable as the optics usually isn't made to withstand that kind of molestation.

[FUTI]

to Jack's Complete: Thanks for the usefull data. But when I asked about heating of the laser diode in modified pointer pen I hoped that heating can be reduced by implementing a small circuitry in place of switch that will allow you to form a time frequency tunable laser pulses (not wavelength of ligth but rather use of short flashes). I hoped that this will make heat disipation better compared to continuous work of laser pointer pen. I'm also gratefull for other solutions proposed by other members regarding cooling of device. Is there something wrong in my logic? If we can't make pointer to work in flashes (altough I don't see the reason why this wouldn't work) maybe we can alter it in other way to modulate the current given to diode so it produce peak power as maximum and normal/declared power as minumum of power output in some time frequency domain. I'm almost certain that I saw declaration on one of the pointers I had saying it has wavelength 560nm and 50mW output but I will go and buy new one to make sure tomorrow. Heating by electromagnetic radiation, and normal cooling through heat sink (conduction) and/or air cooling (convection) are different enough to make me confused is cooling of this laser device (as handheld version) posible. I wouldn't expect anyway that busting of power is remarkable as the optics usually isn't made to withstand that kind of molestation.

[nbk2000]

At the laserglow site, they say that their GBL (expensive) series use a 1.2W (NOT milliwatts, but watt!) IR pumping diode.

Popping balloons and lighting matches with the thing, and that's in the visible (reduced power) green mode.

If I remember correctly, the IR is frequency doubled (or halved) to produce the visible green beam. If you modified it, you could have a powerful IR illuminator/designator instead, as such IR devices are generally considered munitions and restricted accordingly, so this modification may get you one past customs if they allow the green laser through. :)

[nbk2000]

At the laserglow site, they say that their GBL (expensive) series use a 1.2W (NOT milliwatts, but watt!) IR pumping diode.

Popping balloons and lighting matches with the thing, and that's in the visible (reduced power) green mode.

If I remember correctly, the IR is frequency doubled (or halved) to produce the visible green beam. If you modified it, you could have a powerful IR illuminator/designator instead, as such IR devices are generally considered munitions and restricted accordingly, so this modification may get you one past customs if they allow the green laser through. :)

[nbk2000]

At the laserglow site, they say that their GBL (expensive) series use a 1.2W (NOT milliwatts, but watt!) IR pumping diode.

Popping balloons and lighting matches with the thing, and that's in the visible (reduced power) green mode.

If I remember correctly, the IR is frequency doubled (or halved) to produce the visible green beam. If you modified it, you could have a powerful IR illuminator/designator instead, as such IR devices are generally considered munitions and restricted accordingly, so this modification may get you one past customs if they allow the green laser through. :)

[Jacks Complete]

FUTI, I see what you mean.

Yes, you could pulse the output, though it wouldn't make much difference, since the average power would be the same. The only reason to do this would be to exceed some kind of (effectively instantaneous) damage threshold, such as ablation. Welding bulk materials requires high average power, marking requires only high peak powers.

Some (IR) laser diode modules can be pulsed with massive currents with special driver circuits. The risk is that you fry it. I could go and consult about this and get back to you. You can buy very powerful diode modules for material processing.

a_bab,
you are right that you can get the occasional blue laser or yellow. However, yellow is a waste of time, generally, since the response curve of the eye means that the eye is the most sensitive - this is why green is used for NVG goggles. You can see more shades of green than anything else, and your eye is more likely to see it at low levels, and so the power can be kept as low as possible.

Blue diodes are available, and they are very expensive, with very short lifetimes. A few years back, they were cryo cooled and had a lifetime of 15 hours! As ever, you can get almost anything with enough money. However, if you have enough money to waste on a blue laser diode for messing around with, you have enough money to simply buy the diode package direct from the manufacturer at the power output you want. If you want to drop a few K, you can buy any colour laser diode you want, at pretty much whatever power you want.

You can even rig them up with a pigtailed fibre system in an array, and use 40 of them at once to burn holes in things at the IR range. They are efficient, and so you have lower cooling requirements for a given output power. However, there are no advantages to doing this at home. You would do better to invest in a pumped dye laser or something like it.

If you want a portable "laser gun" you could do it, but it would have to be at the IR frequency range to be realistic. Wire 10 of the laser diode modules together, and make sure you buy ones that can pulse up to 40W a peice. Trigger them as you see fit. Either one after another for a second or less, then allow to cool for a while, or pulse them together for ten times the power for a few microseconds. Enough to burn things at a range, depending on optics.

You would have to target the eyes or exposed skin to have effect, and since the pulse will be really, really short, it won't cause much skin damage. It will blow an eyeball nastily, though. However, due to the way the eye works, you are more likely to simply cause a lesion in the back of the eyeball which will mean that the target is blinded in that area of the eye. This is a real bitch if the beam is wide or hits the optic nerve or the fovea centralis (the middle bit you look with of most of the time, in the center)

You would need quite a set of batteries, and things start to get big, but it would be possible to do this. If caught, expect serious jail time - blinding someone will get you put away. Be aware that you will also blind yourself and your friends. Think about any time you played with a laser pen and dazzled yourself for a fraction of a second. Now imagine that had blinded you for three weeks. Now consider the beam isn't even visible, and that would be that.

The only way to treat it would be like a pistol grenade launcher without a safety, and no indication that it was about to fire or had just fired. :eek: Not a tool for the weak-minded.

NBK,
frequency doubling is the same as halving the wavelength. It is a simple ratio around the speed of light. c = f * lambda

Using 1.2 W optical into the little doublers you get in laser pens will fry it, as it will suffer optical damage. The power inside the chip is ten or 100 times higher then the input or output. You can actually see it "ramp up" when you turn it on. :)

You can easily turn a green diode laser pen into an IR laser - just remove the chip and the IR filter. Now it is more powerful, and invisible, and likely to blind you without you knowing till you try to see something that night. Or else you wind up lookin' like ;) or doing a Ray Charles impression :cool: !

[Jacks Complete]

FUTI, I see what you mean.

Yes, you could pulse the output, though it wouldn't make much difference, since the average power would be the same. The only reason to do this would be to exceed some kind of (effectively instantaneous) damage threshold, such as ablation. Welding bulk materials requires high average power, marking requires only high peak powers.

Some (IR) laser diode modules can be pulsed with massive currents with special driver circuits. The risk is that you fry it. I could go and consult about this and get back to you. You can buy very powerful diode modules for material processing.

a_bab,
you are right that you can get the occasional blue laser or yellow. However, yellow is a waste of time, generally, since the response curve of the eye means that the eye is the most sensitive - this is why green is used for NVG goggles. You can see more shades of green than anything else, and your eye is more likely to see it at low levels, and so the power can be kept as low as possible.

Blue diodes are available, and they are very expensive, with very short lifetimes. A few years back, they were cryo cooled and had a lifetime of 15 hours! As ever, you can get almost anything with enough money. However, if you have enough money to waste on a blue laser diode for messing around with, you have enough money to simply buy the diode package direct from the manufacturer at the power output you want. If you want to drop a few K, you can buy any colour laser diode you want, at pretty much whatever power you want.

You can even rig them up with a pigtailed fibre system in an array, and use 40 of them at once to burn holes in things at the IR range. They are efficient, and so you have lower cooling requirements for a given output power. However, there are no advantages to doing this at home. You would do better to invest in a pumped dye laser or something like it.

If you want a portable "laser gun" you could do it, but it would have to be at the IR frequency range to be realistic. Wire 10 of the laser diode modules together, and make sure you buy ones that can pulse up to 40W a peice. Trigger them as you see fit. Either one after another for a second or less, then allow to cool for a while, or pulse them together for ten times the power for a few microseconds. Enough to burn things at a range, depending on optics.

You would have to target the eyes or exposed skin to have effect, and since the pulse will be really, really short, it won't cause much skin damage. It will blow an eyeball nastily, though. However, due to the way the eye works, you are more likely to simply cause a lesion in the back of the eyeball which will mean that the target is blinded in that area of the eye. This is a real bitch if the beam is wide or hits the optic nerve or the fovea centralis (the middle bit you look with of most of the time, in the center)

You would need quite a set of batteries, and things start to get big, but it would be possible to do this. If caught, expect serious jail time - blinding someone will get you put away. Be aware that you will also blind yourself and your friends. Think about any time you played with a laser pen and dazzled yourself for a fraction of a second. Now imagine that had blinded you for three weeks. Now consider the beam isn't even visible, and that would be that.

The only way to treat it would be like a pistol grenade launcher without a safety, and no indication that it was about to fire or had just fired. :eek: Not a tool for the weak-minded.

NBK,
frequency doubling is the same as halving the wavelength. It is a simple ratio around the speed of light. c = f * lambda

Using 1.2 W optical into the little doublers you get in laser pens will fry it, as it will suffer optical damage. The power inside the chip is ten or 100 times higher then the input or output. You can actually see it "ramp up" when you turn it on. :)

You can easily turn a green diode laser pen into an IR laser - just remove the chip and the IR filter. Now it is more powerful, and invisible, and likely to blind you without you knowing till you try to see something that night. Or else you wind up lookin' like ;) or doing a Ray Charles impression :cool: !

[Jacks Complete]

FUTI, I see what you mean.

Yes, you could pulse the output, though it wouldn't make much difference, since the average power would be the same. The only reason to do this would be to exceed some kind of (effectively instantaneous) damage threshold, such as ablation. Welding bulk materials requires high average power, marking requires only high peak powers.

Some (IR) laser diode modules can be pulsed with massive currents with special driver circuits. The risk is that you fry it. I could go and consult about this and get back to you. You can buy very powerful diode modules for material processing.

a_bab,
you are right that you can get the occasional blue laser or yellow. However, yellow is a waste of time, generally, since the response curve of the eye means that the eye is the most sensitive - this is why green is used for NVG goggles. You can see more shades of green than anything else, and your eye is more likely to see it at low levels, and so the power can be kept as low as possible.

Blue diodes are available, and they are very expensive, with very short lifetimes. A few years back, they were cryo cooled and had a lifetime of 15 hours! As ever, you can get almost anything with enough money. However, if you have enough money to waste on a blue laser diode for messing around with, you have enough money to simply buy the diode package direct from the manufacturer at the power output you want. If you want to drop a few K, you can buy any colour laser diode you want, at pretty much whatever power you want.

You can even rig them up with a pigtailed fibre system in an array, and use 40 of them at once to burn holes in things at the IR range. They are efficient, and so you have lower cooling requirements for a given output power. However, there are no advantages to doing this at home. You would do better to invest in a pumped dye laser or something like it.

If you want a portable "laser gun" you could do it, but it would have to be at the IR frequency range to be realistic. Wire 10 of the laser diode modules together, and make sure you buy ones that can pulse up to 40W a peice. Trigger them as you see fit. Either one after another for a second or less, then allow to cool for a while, or pulse them together for ten times the power for a few microseconds. Enough to burn things at a range, depending on optics.

You would have to target the eyes or exposed skin to have effect, and since the pulse will be really, really short, it won't cause much skin damage. It will blow an eyeball nastily, though. However, due to the way the eye works, you are more likely to simply cause a lesion in the back of the eyeball which will mean that the target is blinded in that area of the eye. This is a real bitch if the beam is wide or hits the optic nerve or the fovea centralis (the middle bit you look with of most of the time, in the center)

You would need quite a set of batteries, and things start to get big, but it would be possible to do this. If caught, expect serious jail time - blinding someone will get you put away. Be aware that you will also blind yourself and your friends. Think about any time you played with a laser pen and dazzled yourself for a fraction of a second. Now imagine that had blinded you for three weeks. Now consider the beam isn't even visible, and that would be that.

The only way to treat it would be like a pistol grenade launcher without a safety, and no indication that it was about to fire or had just fired. :eek: Not a tool for the weak-minded.

NBK,
frequency doubling is the same as halving the wavelength. It is a simple ratio around the speed of light. c = f * lambda

Using 1.2 W optical into the little doublers you get in laser pens will fry it, as it will suffer optical damage. The power inside the chip is ten or 100 times higher then the input or output. You can actually see it "ramp up" when you turn it on. :)

You can easily turn a green diode laser pen into an IR laser - just remove the chip and the IR filter. Now it is more powerful, and invisible, and likely to blind you without you knowing till you try to see something that night. Or else you wind up lookin' like ;) or doing a Ray Charles impression :cool: !

[nbk2000]

I could see using such an IR laser for frying pork eyes while they're sitting at a doughnut shop. Right through the window...*sizzzzzPOP!*

Imagine the terror you could cause amoung the pork-bellies! Anytime of night (or day)...*sizzzzPOP!*...at the station, in their car, on foot, in the air...>)

How long till they start wearing blinders or funky googles that render them nearly blind anyways? Mwahahaha!

[nbk2000]

I could see using such an IR laser for frying pork eyes while they're sitting at a doughnut shop. Right through the window...*sizzzzzPOP!*

Imagine the terror you could cause amoung the pork-bellies! Anytime of night (or day)...*sizzzzPOP!*...at the station, in their car, on foot, in the air...>)

How long till they start wearing blinders or funky googles that render them nearly blind anyways? Mwahahaha!

[nbk2000]

I could see using such an IR laser for frying pork eyes while they're sitting at a doughnut shop. Right through the window...*sizzzzzPOP!*

Imagine the terror you could cause amoung the pork-bellies! Anytime of night (or day)...*sizzzzPOP!*...at the station, in their car, on foot, in the air...>)

How long till they start wearing blinders or funky googles that render them nearly blind anyways? Mwahahaha!

[Jacks Complete]

The snag with that is they would have to not be behind glass, since IR doesn't travel through it. You would have to go for something at the very far red end. They would see a slight flash, but nothing else.

A better way might be a hugely powerful Nd:YAG or CO2 with a mirror mount for point defence. Just melt the window away...

[Jacks Complete]

The snag with that is they would have to not be behind glass, since IR doesn't travel through it. You would have to go for something at the very far red end. They would see a slight flash, but nothing else.

A better way might be a hugely powerful Nd:YAG or CO2 with a mirror mount for point defence. Just melt the window away...

[Jacks Complete]

The snag with that is they would have to not be behind glass, since IR doesn't travel through it. You would have to go for something at the very far red end. They would see a slight flash, but nothing else.

A better way might be a hugely powerful Nd:YAG or CO2 with a mirror mount for point defence. Just melt the window away...

[Marvin]

IR from a laser diode for a green DPSS will go through glass fine, its at 808nm. IR from a Nd:YAG also goes through glass with no problem, at about 1032nm. IR from a CO2 laser at 10um or so won't go through glass well and tends to shatter it from localised heating.

UV lasers are no problem with exactly the same technology used for green. DPSS using alexandrite will get you UV anywhere between 350 and 410nm depending on mirrors, or by altering the spec of the green system slightly (additional dichroics not possible to retrofit) you can triple the output to 355nm. The power out for a given pump laser gets a lot worse which is why blue laser pointers cost so much for a lousey output power.

We have decent lifespan UV LEDs at 375nm and below now so I imagine its just a matter of time before a semiconductor UV laser apears. Mass produced blue lasers for blu-ray will be fun but I suspect we'll get cheap blue laser pointers long before its worth searching for dead or secondhand players.

Pulsing semiconductor lasers can be done but the avarage power generally has to be a lot less than the CW power, so no point.

[Marvin]

IR from a laser diode for a green DPSS will go through glass fine, its at 808nm. IR from a Nd:YAG also goes through glass with no problem, at about 1032nm. IR from a CO2 laser at 10um or so won't go through glass well and tends to shatter it from localised heating.

UV lasers are no problem with exactly the same technology used for green. DPSS using alexandrite will get you UV anywhere between 350 and 410nm depending on mirrors, or by altering the spec of the green system slightly (additional dichroics not possible to retrofit) you can triple the output to 355nm. The power out for a given pump laser gets a lot worse which is why blue laser pointers cost so much for a lousey output power.

We have decent lifespan UV LEDs at 375nm and below now so I imagine its just a matter of time before a semiconductor UV laser apears. Mass produced blue lasers for blu-ray will be fun but I suspect we'll get cheap blue laser pointers long before its worth searching for dead or secondhand players.

Pulsing semiconductor lasers can be done but the avarage power generally has to be a lot less than the CW power, so no point.

[Marvin]

IR from a laser diode for a green DPSS will go through glass fine, its at 808nm. IR from a Nd:YAG also goes through glass with no problem, at about 1032nm. IR from a CO2 laser at 10um or so won't go through glass well and tends to shatter it from localised heating.

UV lasers are no problem with exactly the same technology used for green. DPSS using alexandrite will get you UV anywhere between 350 and 410nm depending on mirrors, or by altering the spec of the green system slightly (additional dichroics not possible to retrofit) you can triple the output to 355nm. The power out for a given pump laser gets a lot worse which is why blue laser pointers cost so much for a lousey output power.

We have decent lifespan UV LEDs at 375nm and below now so I imagine its just a matter of time before a semiconductor UV laser apears. Mass produced blue lasers for blu-ray will be fun but I suspect we'll get cheap blue laser pointers long before its worth searching for dead or secondhand players.

Pulsing semiconductor lasers can be done but the avarage power generally has to be a lot less than the CW power, so no point.

[FUTI]

to Jack's Complete: Thanks again. I don't want to make a welding device, cutter or rifle. What I was interested is it posible make pulsed or output power modulated device. As you say it is I will try to make one in some time. But I don't know how does this manipulation affect laser diode lifetime? Can I get longer lifetime as I hoped with this manipulation as well as power busting? I hope this can be true if the working temperature of the diode is the main factor for the lifetime period. I want to make a simple signaling/testing device and light will go through optical cable or solution in isolated box so I hope I'm safe enough ("We'll see!";)).

[FUTI]

to Jack's Complete: Thanks again. I don't want to make a welding device, cutter or rifle. What I was interested is it posible make pulsed or output power modulated device. As you say it is I will try to make one in some time. But I don't know how does this manipulation affect laser diode lifetime? Can I get longer lifetime as I hoped with this manipulation as well as power busting? I hope this can be true if the working temperature of the diode is the main factor for the lifetime period. I want to make a simple signaling/testing device and light will go through optical cable or solution in isolated box so I hope I'm safe enough ("We'll see!";)).

[FUTI]

to Jack's Complete: Thanks again. I don't want to make a welding device, cutter or rifle. What I was interested is it posible make pulsed or output power modulated device. As you say it is I will try to make one in some time. But I don't know how does this manipulation affect laser diode lifetime? Can I get longer lifetime as I hoped with this manipulation as well as power busting? I hope this can be true if the working temperature of the diode is the main factor for the lifetime period. I want to make a simple signaling/testing device and light will go through optical cable or solution in isolated box so I hope I'm safe enough ("We'll see!";)).

[simply RED]

Weren't there IR laser diodes 5-50 watts with colimator and driver already for sale? I remeber once somebody offered me 20 watts IR 1050 or so for 500 bugs...

(Also remember some laser diode series that "Conrad" sale. The presentation of the first 1-Watt diodes in BG (Conrad) was back in 1998. Argh... memmories...)

Laser weapons WILL be decent as they really work!
Nobody could point out where the pulse came from...

[simply RED]

Weren't there IR laser diodes 5-50 watts with colimator and driver already for sale? I remeber once somebody offered me 20 watts IR 1050 or so for 500 bugs...

(Also remember some laser diode series that "Conrad" sale. The presentation of the first 1-Watt diodes in BG (Conrad) was back in 1998. Argh... memmories...)

Laser weapons WILL be decent as they really work!
Nobody could point out where the pulse came from...

[simply RED]

Weren't there IR laser diodes 5-50 watts with colimator and driver already for sale? I remeber once somebody offered me 20 watts IR 1050 or so for 500 bugs...

(Also remember some laser diode series that "Conrad" sale. The presentation of the first 1-Watt diodes in BG (Conrad) was back in 1998. Argh... memmories...)

Laser weapons WILL be decent as they really work!
Nobody could point out where the pulse came from...

[Jacks Complete]

simply RED,
laser weapons don't work well. They are purely line of sight, the firing signature is huge and instant, and easily picked up. The power requirements are bad (just look at the power in a rifle cartridge and compare to a battery!) and the optics are easy to get dirty or damaged. They don't work well in the rain, nor hot sun, nor cloud/mist/fog. Aiming isn't as easy as you think, either, since IR travels differently to visible light (in the same way as you split the colours for a rainbow) Power drops off quite rapidly with distance, too, and you are likely to find yourself getting hit by your own beams, due to the ease of construction of a corner cube, which automatically turns your beam back at you. If you lase a modern tank, they know where you are, too. Anyone with a video camera will also know where you are. And before you say "blind it" all they need is two or more cameras - you can only blind one per shot (if that!) so they have you.

Further, if you have ever been on the far end of a laser beam, the scatter from dust and water, or even the secondary luminesense effects, you would know that the world and his wife can see where you are!

FUTI, if you are using fibres, you don't need a lot of power. The losses will be tiny for anything you are going to do with it, and detection is trivial with a phototransistor or photodiode. Even for a three KM run you won't notice an issue, as long as you get the pigtailing and beam inject sorted. Also, be aware that diode lasers *hate* feedback. You must minimise the light that returns to the laser head.

Marvin,
Yes, if you can find a carefully made tripler chip! Also, as you say, the efficiency gets far worse, meaning you need a heatsink that is bigger, more batteries, lower output, etc. for something that, for the same power, is only half as bright to the eye.

Unless you reach into the UV, there is no point going up the frequency range - you just get more issues with efficiency. Of course, a blue laser would be just that bit cooler than a green laser, but unless you actually want it for the colour, it is a waste of a few thousand dollars.

Also, we have had blue LEDs for over ten years now, and green for far longer. If making green laser diodes was easy (let alone blue) why would anyone make an IR one then add extra parts and expense to make a green pointer?

[Jacks Complete]

simply RED,
laser weapons don't work well. They are purely line of sight, the firing signature is huge and instant, and easily picked up. The power requirements are bad (just look at the power in a rifle cartridge and compare to a battery!) and the optics are easy to get dirty or damaged. They don't work well in the rain, nor hot sun, nor cloud/mist/fog. Aiming isn't as easy as you think, either, since IR travels differently to visible light (in the same way as you split the colours for a rainbow) Power drops off quite rapidly with distance, too, and you are likely to find yourself getting hit by your own beams, due to the ease of construction of a corner cube, which automatically turns your beam back at you. If you lase a modern tank, they know where you are, too. Anyone with a video camera will also know where you are. And before you say "blind it" all they need is two or more cameras - you can only blind one per shot (if that!) so they have you.

Further, if you have ever been on the far end of a laser beam, the scatter from dust and water, or even the secondary luminesense effects, you would know that the world and his wife can see where you are!

FUTI, if you are using fibres, you don't need a lot of power. The losses will be tiny for anything you are going to do with it, and detection is trivial with a phototransistor or photodiode. Even for a three KM run you won't notice an issue, as long as you get the pigtailing and beam inject sorted. Also, be aware that diode lasers *hate* feedback. You must minimise the light that returns to the laser head.

Marvin,
Yes, if you can find a carefully made tripler chip! Also, as you say, the efficiency gets far worse, meaning you need a heatsink that is bigger, more batteries, lower output, etc. for something that, for the same power, is only half as bright to the eye.

Unless you reach into the UV, there is no point going up the frequency range - you just get more issues with efficiency. Of course, a blue laser would be just that bit cooler than a green laser, but unless you actually want it for the colour, it is a waste of a few thousand dollars.

Also, we have had blue LEDs for over ten years now, and green for far longer. If making green laser diodes was easy (let alone blue) why would anyone make an IR one then add extra parts and expense to make a green pointer?

[Jacks Complete]

simply RED,
laser weapons don't work well. They are purely line of sight, the firing signature is huge and instant, and easily picked up. The power requirements are bad (just look at the power in a rifle cartridge and compare to a battery!) and the optics are easy to get dirty or damaged. They don't work well in the rain, nor hot sun, nor cloud/mist/fog. Aiming isn't as easy as you think, either, since IR travels differently to visible light (in the same way as you split the colours for a rainbow) Power drops off quite rapidly with distance, too, and you are likely to find yourself getting hit by your own beams, due to the ease of construction of a corner cube, which automatically turns your beam back at you. If you lase a modern tank, they know where you are, too. Anyone with a video camera will also know where you are. And before you say "blind it" all they need is two or more cameras - you can only blind one per shot (if that!) so they have you.

Further, if you have ever been on the far end of a laser beam, the scatter from dust and water, or even the secondary luminesense effects, you would know that the world and his wife can see where you are!

FUTI, if you are using fibres, you don't need a lot of power. The losses will be tiny for anything you are going to do with it, and detection is trivial with a phototransistor or photodiode. Even for a three KM run you won't notice an issue, as long as you get the pigtailing and beam inject sorted. Also, be aware that diode lasers *hate* feedback. You must minimise the light that returns to the laser head.

Marvin,
Yes, if you can find a carefully made tripler chip! Also, as you say, the efficiency gets far worse, meaning you need a heatsink that is bigger, more batteries, lower output, etc. for something that, for the same power, is only half as bright to the eye.

Unless you reach into the UV, there is no point going up the frequency range - you just get more issues with efficiency. Of course, a blue laser would be just that bit cooler than a green laser, but unless you actually want it for the colour, it is a waste of a few thousand dollars.

Also, we have had blue LEDs for over ten years now, and green for far longer. If making green laser diodes was easy (let alone blue) why would anyone make an IR one then add extra parts and expense to make a green pointer?

[simply RED]

I have not dealed with lasers for 3 years. But remember that IR LEDs are many times cheaper and more powerful than visible LEDs. Thats why it is prefered to use IR LED as a pumping source and then multiply the frequency by non- linear optics ( whatever it means :) ).

Sincerely said... They have no protection from lasers.
Maybe if you fire once, twice, they may do some protection activities. But at the present times no protection or detection of microwaves up to gama rays exists.

You may fire at all frequency range from 30GHz and above and will not be detected (unless VISible light is used).

That includes microwave weapons with possibility of creating psychotronic weapons (never seen such to work) , IR blinding and burning lasers, UV, Ro, gama. From these, I guess, IR are easiest to use.

Yes, I know that aiming is a pain in the ass. Anyway - an enthusiast will cope with the problem.

[simply RED]

I have not dealed with lasers for 3 years. But remember that IR LEDs are many times cheaper and more powerful than visible LEDs. Thats why it is prefered to use IR LED as a pumping source and then multiply the frequency by non- linear optics ( whatever it means :) ).

Sincerely said... They have no protection from lasers.
Maybe if you fire once, twice, they may do some protection activities. But at the present times no protection or detection of microwaves up to gama rays exists.

You may fire at all frequency range from 30GHz and above and will not be detected (unless VISible light is used).

That includes microwave weapons with possibility of creating psychotronic weapons (never seen such to work) , IR blinding and burning lasers, UV, Ro, gama. From these, I guess, IR are easiest to use.

Yes, I know that aiming is a pain in the ass. Anyway - an enthusiast will cope with the problem.

[simply RED]

I have not dealed with lasers for 3 years. But remember that IR LEDs are many times cheaper and more powerful than visible LEDs. Thats why it is prefered to use IR LED as a pumping source and then multiply the frequency by non- linear optics ( whatever it means :) ).

Sincerely said... They have no protection from lasers.
Maybe if you fire once, twice, they may do some protection activities. But at the present times no protection or detection of microwaves up to gama rays exists.

You may fire at all frequency range from 30GHz and above and will not be detected (unless VISible light is used).

That includes microwave weapons with possibility of creating psychotronic weapons (never seen such to work) , IR blinding and burning lasers, UV, Ro, gama. From these, I guess, IR are easiest to use.

Yes, I know that aiming is a pain in the ass. Anyway - an enthusiast will cope with the problem.

[Jacks Complete]

I typed a huge response to simply RED's post, but the server was too busy, and I lost it.

To recap: LEDs are not lasers, if they were, then why spend lots on a laser if a 29p LED would do the job? They aren't used to pump things. Flashlamps and other lasers are.

Any freq. can be detected. CCDs pick up UV, vis. and near IR. Tanks know which building to level when you laser range them due to detector on turret.

NVGs pick up near IR insanely well, as do small B&W video cameras. Thermal imagers detect long wavelength IR.

Sunglasses stop 90% of damage. IR and UV are blocked, plus ~15% of visible light.

I also recapped on the troubles getting shorter frequencies, and that the reason we have green laser pens is because it is cheaper to build them with a doubler, using more parts, than it is to build an actual green diode, let alone blue ones.

Aiming is easy, hitting is hard. Power drops with beam spread over ranges, but tight spot is far harder to hit target with. Head shots at 500yards are difficult, even though you can see the target because IR travels a bit differently to visible light. IR gets absorbed by water in air far more than visible light. Doesn't work when misty or raining, etc.

[Jacks Complete]

I typed a huge response to simply RED's post, but the server was too busy, and I lost it.

To recap: LEDs are not lasers, if they were, then why spend lots on a laser if a 29p LED would do the job? They aren't used to pump things. Flashlamps and other lasers are.

Any freq. can be detected. CCDs pick up UV, vis. and near IR. Tanks know which building to level when you laser range them due to detector on turret.

NVGs pick up near IR insanely well, as do small B&W video cameras. Thermal imagers detect long wavelength IR.

Sunglasses stop 90% of damage. IR and UV are blocked, plus ~15% of visible light.

I also recapped on the troubles getting shorter frequencies, and that the reason we have green laser pens is because it is cheaper to build them with a doubler, using more parts, than it is to build an actual green diode, let alone blue ones.

Aiming is easy, hitting is hard. Power drops with beam spread over ranges, but tight spot is far harder to hit target with. Head shots at 500yards are difficult, even though you can see the target because IR travels a bit differently to visible light. IR gets absorbed by water in air far more than visible light. Doesn't work when misty or raining, etc.

[Jacks Complete]

I typed a huge response to simply RED's post, but the server was too busy, and I lost it.

To recap: LEDs are not lasers, if they were, then why spend lots on a laser if a 29p LED would do the job? They aren't used to pump things. Flashlamps and other lasers are.

Any freq. can be detected. CCDs pick up UV, vis. and near IR. Tanks know which building to level when you laser range them due to detector on turret.

NVGs pick up near IR insanely well, as do small B&W video cameras. Thermal imagers detect long wavelength IR.

Sunglasses stop 90% of damage. IR and UV are blocked, plus ~15% of visible light.

I also recapped on the troubles getting shorter frequencies, and that the reason we have green laser pens is because it is cheaper to build them with a doubler, using more parts, than it is to build an actual green diode, let alone blue ones.

Aiming is easy, hitting is hard. Power drops with beam spread over ranges, but tight spot is far harder to hit target with. Head shots at 500yards are difficult, even though you can see the target because IR travels a bit differently to visible light. IR gets absorbed by water in air far more than visible light. Doesn't work when misty or raining, etc.

[FUTI]

to Jack's Complete: Thanks for explanation. It seem that I won't need stronger light source, but I will have to reduce the path of light through the testing solution in order to cut the intensity drop to resonable level. I try to make the detector volume as small as posible and that is why I'm thinking of using fibers as mean of "introducing" light into detector "chamber". In my opinion it would simplify the device very much, but as nothing is perfect - it has its flaws. I was hoping to make modulated power souce to counteract with some of the flaws/difficulties so that's why this thread gain my attention. Timed pulses are simple and obtainable solution, but I'm more fond of using power/intensity modulated pulses, as it give me more space for experiments and improvement. This time I have 3 question.
1. As LED based lasers aren't real lasers as they aren't monochromatic and have about 10nm range will this afect performance significantly? You know interference or something...
2. If I'm unable to avoid power modulation as mean of signal confirmation/improvement and decide to make one but still in the limits of prescribed power output for the device, will the simple modulation of the electric current (i) do the job (as grendel23 proposed above)?
3. Detection of signal is important and meaning of all said avobe is conected to this one. Will simple photodiode or phototransistor be able to work in that regime? I was thinking to use photocell for its wider detection in fear of that 10nm wide source, but then when you posted above it was like "logic bomb" to my knowledge (which is maybe signal of insuficient knowledge or data or both). I can understand how photodiode or phototransistor can detect light and duration of signal, but I can hardly imagine that it can detect power modulated signal the exactly the way it looks.

[FUTI]

to Jack's Complete: Thanks for explanation. It seem that I won't need stronger light source, but I will have to reduce the path of light through the testing solution in order to cut the intensity drop to resonable level. I try to make the detector volume as small as posible and that is why I'm thinking of using fibers as mean of "introducing" light into detector "chamber". In my opinion it would simplify the device very much, but as nothing is perfect - it has its flaws. I was hoping to make modulated power souce to counteract with some of the flaws/difficulties so that's why this thread gain my attention. Timed pulses are simple and obtainable solution, but I'm more fond of using power/intensity modulated pulses, as it give me more space for experiments and improvement. This time I have 3 question.
1. As LED based lasers aren't real lasers as they aren't monochromatic and have about 10nm range will this afect performance significantly? You know interference or something...
2. If I'm unable to avoid power modulation as mean of signal confirmation/improvement and decide to make one but still in the limits of prescribed power output for the device, will the simple modulation of the electric current (i) do the job (as grendel23 proposed above)?
3. Detection of signal is important and meaning of all said avobe is conected to this one. Will simple photodiode or phototransistor be able to work in that regime? I was thinking to use photocell for its wider detection in fear of that 10nm wide source, but then when you posted above it was like "logic bomb" to my knowledge (which is maybe signal of insuficient knowledge or data or both). I can understand how photodiode or phototransistor can detect light and duration of signal, but I can hardly imagine that it can detect power modulated signal the exactly the way it looks.

[FUTI]

to Jack's Complete: Thanks for explanation. It seem that I won't need stronger light source, but I will have to reduce the path of light through the testing solution in order to cut the intensity drop to resonable level. I try to make the detector volume as small as posible and that is why I'm thinking of using fibers as mean of "introducing" light into detector "chamber". In my opinion it would simplify the device very much, but as nothing is perfect - it has its flaws. I was hoping to make modulated power souce to counteract with some of the flaws/difficulties so that's why this thread gain my attention. Timed pulses are simple and obtainable solution, but I'm more fond of using power/intensity modulated pulses, as it give me more space for experiments and improvement. This time I have 3 question.
1. As LED based lasers aren't real lasers as they aren't monochromatic and have about 10nm range will this afect performance significantly? You know interference or something...
2. If I'm unable to avoid power modulation as mean of signal confirmation/improvement and decide to make one but still in the limits of prescribed power output for the device, will the simple modulation of the electric current (i) do the job (as grendel23 proposed above)?
3. Detection of signal is important and meaning of all said avobe is conected to this one. Will simple photodiode or phototransistor be able to work in that regime? I was thinking to use photocell for its wider detection in fear of that 10nm wide source, but then when you posted above it was like "logic bomb" to my knowledge (which is maybe signal of insuficient knowledge or data or both). I can understand how photodiode or phototransistor can detect light and duration of signal, but I can hardly imagine that it can detect power modulated signal the exactly the way it looks.

[simply RED]

NOOOOOO

I wrote the reply 3 hours and it halted.......

Anyway:
1
http://groups.google.com/groups?q=diode+pumped&hl=bg&lr=&selm=6ncmk1%24fu4%241%40pula.financenet.gov&rnum=1
see how are the modern lasers pumped.
see alt.lasers too.
And i was explaining with the quantum theory why diodes must be used but not a lamp. Because the wavelenghth must fall in the "excitement spectra". And must be monochromatic, not that diodes are but are near.

2 No defense exists for the civil population. I KNOW FROM FUCKING EXPERIENCE.
I have "experimented" with kilowatts of 1kHz - 2700 MHz. And watts of IR for 2 years every day for 8 hours, destroyed numerous electric devices! Used 5mW red pointer to detonate 200 grams device. And noone ever said something.
See the reality!
Only the most advanced armies have any defense. (BG army does not have).
Short pulses are impossible to detect! Tanks are not to be shoot with a laser or MW. Only planes and people. (there was a report in the news somebody illuminated a plane with powerful green laser. Do they catch him? )

3 FUTI, what device are you trying to make? Why is detector needed.

4. Jacks Complete, absoluitely right! Lasers have low range!
20 mW IR could be used to aim the 5 watts one. and you will be the one with the googles to see the spot, not the hams!

5. I would like to have the microwave spectra of GABA in diluted solution. Anyway such subjects are tabu and "we" only take some pussy-chemicals spectra.

[simply RED]

NOOOOOO

I wrote the reply 3 hours and it halted.......

Anyway:
1
http://groups.google.com/groups?q=diode+pumped&hl=bg&lr=&selm=6ncmk1%24fu4%241%40pula.financenet.gov&rnum=1
see how are the modern lasers pumped.
see alt.lasers too.
And i was explaining with the quantum theory why diodes must be used but not a lamp. Because the wavelenghth must fall in the "excitement spectra". And must be monochromatic, not that diodes are but are near.

2 No defense exists for the civil population. I KNOW FROM FUCKING EXPERIENCE.
I have "experimented" with kilowatts of 1kHz - 2700 MHz. And watts of IR for 2 years every day for 8 hours, destroyed numerous electric devices! Used 5mW red pointer to detonate 200 grams device. And noone ever said something.
See the reality!
Only the most advanced armies have any defense. (BG army does not have).
Short pulses are impossible to detect! Tanks are not to be shoot with a laser or MW. Only planes and people. (there was a report in the news somebody illuminated a plane with powerful green laser. Do they catch him? )

3 FUTI, what device are you trying to make? Why is detector needed.

4. Jacks Complete, absoluitely right! Lasers have low range!
20 mW IR could be used to aim the 5 watts one. and you will be the one with the googles to see the spot, not the hams!

5. I would like to have the microwave spectra of GABA in diluted solution. Anyway such subjects are tabu and "we" only take some pussy-chemicals spectra.

[simply RED]

NOOOOOO

I wrote the reply 3 hours and it halted.......

Anyway:
1
http://groups.google.com/groups?q=diode+pumped&hl=bg&lr=&selm=6ncmk1%24fu4%241%40pula.financenet.gov&rnum=1
see how are the modern lasers pumped.
see alt.lasers too.
And i was explaining with the quantum theory why diodes must be used but not a lamp. Because the wavelenghth must fall in the "excitement spectra". And must be monochromatic, not that diodes are but are near.

2 No defense exists for the civil population. I KNOW FROM FUCKING EXPERIENCE.
I have "experimented" with kilowatts of 1kHz - 2700 MHz. And watts of IR for 2 years every day for 8 hours, destroyed numerous electric devices! Used 5mW red pointer to detonate 200 grams device. And noone ever said something.
See the reality!
Only the most advanced armies have any defense. (BG army does not have).
Short pulses are impossible to detect! Tanks are not to be shoot with a laser or MW. Only planes and people. (there was a report in the news somebody illuminated a plane with powerful green laser. Do they catch him? )

3 FUTI, what device are you trying to make? Why is detector needed.

4. Jacks Complete, absoluitely right! Lasers have low range!
20 mW IR could be used to aim the 5 watts one. and you will be the one with the googles to see the spot, not the hams!

5. I would like to have the microwave spectra of GABA in diluted solution. Anyway such subjects are tabu and "we" only take some pussy-chemicals spectra.

[FUTI]

simply RED I don't make device. Detector is the goal. I'm trying to make somthing that can measure one of the following parameters: index of refraction, transparence or adsorption to surface. First parameter is best to be detected by monochromatic light so I choose LED laser pen(well sodium D-line would be better, but what the heck this is cheapest and closest I can get in homemade construction), for the second parameter it would be best if I have several LED laser pen of diferent colour (like red, blue and green) to make some kind of primitive photocolorimeter (although red is fine as far as I'm concerned but I started to worry little what if turbidity of solution give me false signal augmentation or noise so thats why blue LED (as that wavelength is more prone to that) would serve as control probe.... - I'm still working to solve that one completely). Adsorption is simple, photodiode is covered with transparent material and adsorption of molecules from solution changes its spectral caracteristics (transparency). I was hoping that use of fibers will reduce optical elements (mirrors, lenses etc.) to minimum and that rest of the design flaws can be counteracted with digital conversion/sampling of the signal even if it reduce response time of the device. If anyone can help me with this please send me a PM as posting seems to be little dificult lately.

Hell, I have ethyl ester of GABA, but don't have where to record the spectra! You have the can, I have the can opener or is it other way around. Anyway why do you need that spectra?

[FUTI]

simply RED I don't make device. Detector is the goal. I'm trying to make somthing that can measure one of the following parameters: index of refraction, transparence or adsorption to surface. First parameter is best to be detected by monochromatic light so I choose LED laser pen(well sodium D-line would be better, but what the heck this is cheapest and closest I can get in homemade construction), for the second parameter it would be best if I have several LED laser pen of diferent colour (like red, blue and green) to make some kind of primitive photocolorimeter (although red is fine as far as I'm concerned but I started to worry little what if turbidity of solution give me false signal augmentation or noise so thats why blue LED (as that wavelength is more prone to that) would serve as control probe.... - I'm still working to solve that one completely). Adsorption is simple, photodiode is covered with transparent material and adsorption of molecules from solution changes its spectral caracteristics (transparency). I was hoping that use of fibers will reduce optical elements (mirrors, lenses etc.) to minimum and that rest of the design flaws can be counteracted with digital conversion/sampling of the signal even if it reduce response time of the device. If anyone can help me with this please send me a PM as posting seems to be little dificult lately.

Hell, I have ethyl ester of GABA, but don't have where to record the spectra! You have the can, I have the can opener or is it other way around. Anyway why do you need that spectra?

[FUTI]

simply RED I don't make device. Detector is the goal. I'm trying to make somthing that can measure one of the following parameters: index of refraction, transparence or adsorption to surface. First parameter is best to be detected by monochromatic light so I choose LED laser pen(well sodium D-line would be better, but what the heck this is cheapest and closest I can get in homemade construction), for the second parameter it would be best if I have several LED laser pen of diferent colour (like red, blue and green) to make some kind of primitive photocolorimeter (although red is fine as far as I'm concerned but I started to worry little what if turbidity of solution give me false signal augmentation or noise so thats why blue LED (as that wavelength is more prone to that) would serve as control probe.... - I'm still working to solve that one completely). Adsorption is simple, photodiode is covered with transparent material and adsorption of molecules from solution changes its spectral caracteristics (transparency). I was hoping that use of fibers will reduce optical elements (mirrors, lenses etc.) to minimum and that rest of the design flaws can be counteracted with digital conversion/sampling of the signal even if it reduce response time of the device. If anyone can help me with this please send me a PM as posting seems to be little dificult lately.

Hell, I have ethyl ester of GABA, but don't have where to record the spectra! You have the can, I have the can opener or is it other way around. Anyway why do you need that spectra?

[Jacks Complete]

FUTI,
can you explain exactly what you are making? Is it a fibre-based comms device? Why do you want to modulate the power, rather than simply switch? Are you after some kind of analogue system, rather than digital?

A photodiode will happily respond with a voltage that is proportional to the incident light, as long as you don't saturate the device. You could do this wil even just a low powered LED over short distances.

However, as I type this, you have posted again. The problem with your detector for spectra is that it would be using a (almost) monochromatic light beam. This means it won't work. To detect the absorbed frequencies, you need all the frequencies to be there first. You then measure the spectra, and add your sample. Take the spectra again, and subtract the first run to get a flat response curve.
Easiest way to do this is a photodiode, a transparent quartz cell, a ruled diffraction grating, some tubes and things, and an incadescent bulb (none halogen). If combined with a data capture card and a position measurement device to record the angle at the same time as the incident power, you would have quite a professional bit of kit. You don't need fibres or any more optics than a lense to get a nice beam off your lamp, or to expand the beam so you get higher precision readings by expanding the beam angle after the grating.

simply RED,
yes, you can pump using a diode, but it is rare. You have to get the diode to lase at just the right frequency for the stimulation of your target laser material. Done just right, you get very high efficiency, done not quite right, you get nothing but melted optics. And you certainly cannot run a diode into a frequency doubler chip.

Using a diode laser as a pump is very much more efficient than a flashlamp, but believe me, most lasers (by type) are pumped by other lasers, or by a flashlamp. In pure numbers, most lasers are pumped by electricity, either via a diode's current injection, or by the high voltage arc of a He-Ne. I reckon 99%+ of all lasers are diode lasers, and 99%+ of the 1% are He-Ne.

Also, note that nowhere did I say lasers have short range! I can light up a plane at 40 miles (in theory) since I can see it! However, I do like your idea of having a low powered IR diode laser slaved to a 5W laser. Better, however, might be a Q-switched system. The pump will leak then fire a pulse. You could then use the same lower power laser to do both jobs.

[Jacks Complete]

FUTI,
can you explain exactly what you are making? Is it a fibre-based comms device? Why do you want to modulate the power, rather than simply switch? Are you after some kind of analogue system, rather than digital?

A photodiode will happily respond with a voltage that is proportional to the incident light, as long as you don't saturate the device. You could do this wil even just a low powered LED over short distances.

However, as I type this, you have posted again. The problem with your detector for spectra is that it would be using a (almost) monochromatic light beam. This means it won't work. To detect the absorbed frequencies, you need all the frequencies to be there first. You then measure the spectra, and add your sample. Take the spectra again, and subtract the first run to get a flat response curve.
Easiest way to do this is a photodiode, a transparent quartz cell, a ruled diffraction grating, some tubes and things, and an incadescent bulb (none halogen). If combined with a data capture card and a position measurement device to record the angle at the same time as the incident power, you would have quite a professional bit of kit. You don't need fibres or any more optics than a lense to get a nice beam off your lamp, or to expand the beam so you get higher precision readings by expanding the beam angle after the grating.

simply RED,
yes, you can pump using a diode, but it is rare. You have to get the diode to lase at just the right frequency for the stimulation of your target laser material. Done just right, you get very high efficiency, done not quite right, you get nothing but melted optics. And you certainly cannot run a diode into a frequency doubler chip.

Using a diode laser as a pump is very much more efficient than a flashlamp, but believe me, most lasers (by type) are pumped by other lasers, or by a flashlamp. In pure numbers, most lasers are pumped by electricity, either via a diode's current injection, or by the high voltage arc of a He-Ne. I reckon 99%+ of all lasers are diode lasers, and 99%+ of the 1% are He-Ne.

Also, note that nowhere did I say lasers have short range! I can light up a plane at 40 miles (in theory) since I can see it! However, I do like your idea of having a low powered IR diode laser slaved to a 5W laser. Better, however, might be a Q-switched system. The pump will leak then fire a pulse. You could then use the same lower power laser to do both jobs.

[Jacks Complete]

FUTI,
can you explain exactly what you are making? Is it a fibre-based comms device? Why do you want to modulate the power, rather than simply switch? Are you after some kind of analogue system, rather than digital?

A photodiode will happily respond with a voltage that is proportional to the incident light, as long as you don't saturate the device. You could do this wil even just a low powered LED over short distances.

However, as I type this, you have posted again. The problem with your detector for spectra is that it would be using a (almost) monochromatic light beam. This means it won't work. To detect the absorbed frequencies, you need all the frequencies to be there first. You then measure the spectra, and add your sample. Take the spectra again, and subtract the first run to get a flat response curve.
Easiest way to do this is a photodiode, a transparent quartz cell, a ruled diffraction grating, some tubes and things, and an incadescent bulb (none halogen). If combined with a data capture card and a position measurement device to record the angle at the same time as the incident power, you would have quite a professional bit of kit. You don't need fibres or any more optics than a lense to get a nice beam off your lamp, or to expand the beam so you get higher precision readings by expanding the beam angle after the grating.

simply RED,
yes, you can pump using a diode, but it is rare. You have to get the diode to lase at just the right frequency for the stimulation of your target laser material. Done just right, you get very high efficiency, done not quite right, you get nothing but melted optics. And you certainly cannot run a diode into a frequency doubler chip.

Using a diode laser as a pump is very much more efficient than a flashlamp, but believe me, most lasers (by type) are pumped by other lasers, or by a flashlamp. In pure numbers, most lasers are pumped by electricity, either via a diode's current injection, or by the high voltage arc of a He-Ne. I reckon 99%+ of all lasers are diode lasers, and 99%+ of the 1% are He-Ne.

Also, note that nowhere did I say lasers have short range! I can light up a plane at 40 miles (in theory) since I can see it! However, I do like your idea of having a low powered IR diode laser slaved to a 5W laser. Better, however, might be a Q-switched system. The pump will leak then fire a pulse. You could then use the same lower power laser to do both jobs.

[akinrog]

While searching, I run onto this link (http://www.technology.niagarac.on.ca/people/mcsele/lasers/LasersN2.htm). It's related to the N2 (i.e. air) lasers. And there is a reference at the bottom of the page (Reference [6] A simple, high power nitrogen laser
D. Basting, et al. etc. etc.) it states its power output is 1.2 MW. Can it be deployed to some good uses (with regard to of course E&W related uses)?

[akinrog]

While searching, I run onto this link (http://www.technology.niagarac.on.ca/people/mcsele/lasers/LasersN2.htm). It's related to the N2 (i.e. air) lasers. And there is a reference at the bottom of the page (Reference [6] A simple, high power nitrogen laser
D. Basting, et al. etc. etc.) it states its power output is 1.2 MW. Can it be deployed to some good uses (with regard to of course E&W related uses)?

[akinrog]

While searching, I run onto this link (http://www.technology.niagarac.on.ca/people/mcsele/lasers/LasersN2.htm). It's related to the N2 (i.e. air) lasers. And there is a reference at the bottom of the page (Reference [6] A simple, high power nitrogen laser
D. Basting, et al. etc. etc.) it states its power output is 1.2 MW. Can it be deployed to some good uses (with regard to of course E&W related uses)?

[FUTI]

to Jack's Complete: Thanks. Your posts were very helpfull. You resolved some "dark places" that I had no courage to go in, but have vague sense they are outthere waiting for me to to stumble on them and bust my nose. I know that it wont record full spectra. It was never intended. The compound I'm chasing have its max absorption at the same wavelength as LED diode laser I want to use so it is actually simpler then that. The idea of using several diodes were highly hipotetical and just rough drawing induced by fear of several absorption mechanism acting together. I agree with everything you said and proposed scematics of detector but where I'm living grating isn't really "homemade" or easy obtainable part of equipment. I will let you know what did I manage to do in a month or two. I think that index of refraction isn't questionable so I think one of three posible parameters I can't miss.

[FUTI]

to Jack's Complete: Thanks. Your posts were very helpfull. You resolved some "dark places" that I had no courage to go in, but have vague sense they are outthere waiting for me to to stumble on them and bust my nose. I know that it wont record full spectra. It was never intended. The compound I'm chasing have its max absorption at the same wavelength as LED diode laser I want to use so it is actually simpler then that. The idea of using several diodes were highly hipotetical and just rough drawing induced by fear of several absorption mechanism acting together. I agree with everything you said and proposed scematics of detector but where I'm living grating isn't really "homemade" or easy obtainable part of equipment. I will let you know what did I manage to do in a month or two. I think that index of refraction isn't questionable so I think one of three posible parameters I can't miss.

[FUTI]

to Jack's Complete: Thanks. Your posts were very helpfull. You resolved some "dark places" that I had no courage to go in, but have vague sense they are outthere waiting for me to to stumble on them and bust my nose. I know that it wont record full spectra. It was never intended. The compound I'm chasing have its max absorption at the same wavelength as LED diode laser I want to use so it is actually simpler then that. The idea of using several diodes were highly hipotetical and just rough drawing induced by fear of several absorption mechanism acting together. I agree with everything you said and proposed scematics of detector but where I'm living grating isn't really "homemade" or easy obtainable part of equipment. I will let you know what did I manage to do in a month or two. I think that index of refraction isn't questionable so I think one of three posible parameters I can't miss.

[simply RED]

The microwave specter of GABA in solution is inetersting because
the molecule H3N(+)-CH2-CH2-CH2-COO(-) is very possibly active as MW absorbent (it is a perfect dipole). The microwaves should affect the "rotational energy" of the molecule.
{IR affects vibrational energy, UV - electron energy, radiowaves are associated with "magnetic" changes.)
Anyway the specter may not have a good maximum but rather wide peak due to solvatation processes and solution energy transfer (heating).

As a fact, GABA is one of the most valuable CNS mediators. Chaging its energy will cause malfunctions of the GABA- receptor aparatus.
In other words, the peak absorbtion wavelength may be psychoactive.

(It may be like the MW oven heats the water but not the porcelain dish.)

I have serious materials (Soviet "Toxicology and Pharmacology magazine(for professional use) ") about a russian MW experiments (not quite interesting, may type it here some day). Anyway, they use brutal force and don't use particular frequency, just the easiest to generate. The device kills mice at range (200 meters). Mice die due to CNS and hearth failure.
Russians even found that doping mice with some chemical (don't remember what) acts like defense and mice need higher doses MW radiation to die.
But they only killed the mice and never tried how the MW affect their behaviour.

Back on topic:

Visible spectrometers (SPEKOL) series first desintegrate white light to all frequences with a difraction latice or prism. You can adjust what wavelength to use to illuminate the sample by a rotating key on the apparatus.
So, you chose the wavelength , put there your sample in a cuvette and measure absorbtion.
I have done experiments with SPEKOL-12 (12 if i remember correctly) to measure absorbtion from 400 to 500 nm of a metal complex molecule , measuring was made in every 10 nm. And then a graphic was drawn to show the spectra of the complex in this wavelength range.
If adjustable laser is available. Is it? The measurement will be more precise.
To measure quantity using absorbtion law, you need the peak of the spectra, so no laser will work (unless in the peak or adjustable).

[simply RED]

The microwave specter of GABA in solution is inetersting because
the molecule H3N(+)-CH2-CH2-CH2-COO(-) is very possibly active as MW absorbent (it is a perfect dipole). The microwaves should affect the "rotational energy" of the molecule.
{IR affects vibrational energy, UV - electron energy, radiowaves are associated with "magnetic" changes.)
Anyway the specter may not have a good maximum but rather wide peak due to solvatation processes and solution energy transfer (heating).

As a fact, GABA is one of the most valuable CNS mediators. Chaging its energy will cause malfunctions of the GABA- receptor aparatus.
In other words, the peak absorbtion wavelength may be psychoactive.

(It may be like the MW oven heats the water but not the porcelain dish.)

I have serious materials (Soviet "Toxicology and Pharmacology magazine(for professional use) ") about a russian MW experiments (not quite interesting, may type it here some day). Anyway, they use brutal force and don't use particular frequency, just the easiest to generate. The device kills mice at range (200 meters). Mice die due to CNS and hearth failure.
Russians even found that doping mice with some chemical (don't remember what) acts like defense and mice need higher doses MW radiation to die.
But they only killed the mice and never tried how the MW affect their behaviour.

Back on topic:

Visible spectrometers (SPEKOL) series first desintegrate white light to all frequences with a difraction latice or prism. You can adjust what wavelength to use to illuminate the sample by a rotating key on the apparatus.
So, you chose the wavelength , put there your sample in a cuvette and measure absorbtion.
I have done experiments with SPEKOL-12 (12 if i remember correctly) to measure absorbtion from 400 to 500 nm of a metal complex molecule , measuring was made in every 10 nm. And then a graphic was drawn to show the spectra of the complex in this wavelength range.
If adjustable laser is available. Is it? The measurement will be more precise.
To measure quantity using absorbtion law, you need the peak of the spectra, so no laser will work (unless in the peak or adjustable).

[simply RED]

The microwave specter of GABA in solution is inetersting because
the molecule H3N(+)-CH2-CH2-CH2-COO(-) is very possibly active as MW absorbent (it is a perfect dipole). The microwaves should affect the "rotational energy" of the molecule.
{IR affects vibrational energy, UV - electron energy, radiowaves are associated with "magnetic" changes.)
Anyway the specter may not have a good maximum but rather wide peak due to solvatation processes and solution energy transfer (heating).

As a fact, GABA is one of the most valuable CNS mediators. Chaging its energy will cause malfunctions of the GABA- receptor aparatus.
In other words, the peak absorbtion wavelength may be psychoactive.

(It may be like the MW oven heats the water but not the porcelain dish.)

I have serious materials (Soviet "Toxicology and Pharmacology magazine(for professional use) ") about a russian MW experiments (not quite interesting, may type it here some day). Anyway, they use brutal force and don't use particular frequency, just the easiest to generate. The device kills mice at range (200 meters). Mice die due to CNS and hearth failure.
Russians even found that doping mice with some chemical (don't remember what) acts like defense and mice need higher doses MW radiation to die.
But they only killed the mice and never tried how the MW affect their behaviour.

Back on topic:

Visible spectrometers (SPEKOL) series first desintegrate white light to all frequences with a difraction latice or prism. You can adjust what wavelength to use to illuminate the sample by a rotating key on the apparatus.
So, you chose the wavelength , put there your sample in a cuvette and measure absorbtion.
I have done experiments with SPEKOL-12 (12 if i remember correctly) to measure absorbtion from 400 to 500 nm of a metal complex molecule , measuring was made in every 10 nm. And then a graphic was drawn to show the spectra of the complex in this wavelength range.
If adjustable laser is available. Is it? The measurement will be more precise.
To measure quantity using absorbtion law, you need the peak of the spectra, so no laser will work (unless in the peak or adjustable).

[Jacks Complete]

akinrog, That's for a self-terminating 90ns pulsed UV laser. Very smart, runs off air and electric!

FUTI, anything with closely spaced lines will do - a CD, even, or (a poor second) a glass prism.

Anything that you can throw a rainbow onto the wall with from the sunlight will work.

The best way, as simply RED says, would be a tunable laser pointing through the cell, with the detector on the other side. Then just scroll through the frequencies and record the absorbtion. Having a laser at the absorbtion peak won't really tell you anything, though.

[Jacks Complete]

akinrog, That's for a self-terminating 90ns pulsed UV laser. Very smart, runs off air and electric!

FUTI, anything with closely spaced lines will do - a CD, even, or (a poor second) a glass prism.

Anything that you can throw a rainbow onto the wall with from the sunlight will work.

The best way, as simply RED says, would be a tunable laser pointing through the cell, with the detector on the other side. Then just scroll through the frequencies and record the absorbtion. Having a laser at the absorbtion peak won't really tell you anything, though.

[Jacks Complete]

akinrog, That's for a self-terminating 90ns pulsed UV laser. Very smart, runs off air and electric!

FUTI, anything with closely spaced lines will do - a CD, even, or (a poor second) a glass prism.

Anything that you can throw a rainbow onto the wall with from the sunlight will work.

The best way, as simply RED says, would be a tunable laser pointing through the cell, with the detector on the other side. Then just scroll through the frequencies and record the absorbtion. Having a laser at the absorbtion peak won't really tell you anything, though.

[Marvin]

FUTI,

You are correct but you need to split the laser beam and have a detector on each. One beam has the same in, the other just measures the relative strength of the beam with nothing absorbing. If you know these values and the path length that gets you the concentration of the chemical in the solution. I assume its what you are after. Additional beams are only important if you have interfering chemicals in the solution as well.

Akinrog,

Nitrogen laser has impressive sounding power, but its pulses are less than 10ns long typically. The energy per pulse is very very small. The beam is also virtually impossible to focus, unlike an ordinary laser.


Jack, Red,

UV/Vis spectrometers for me were the dullest things Ive ever used, they tell you virtually nothing about the molecule. Ive heard good things about looking into a glass prism with a telescope for atomic line spectra. CD's dont disperse that cleanly, mainly becuase they arnt straight lines, good enough for working out the frequency of a laser pointer but not much else.

[Marvin]

FUTI,

You are correct but you need to split the laser beam and have a detector on each. One beam has the same in, the other just measures the relative strength of the beam with nothing absorbing. If you know these values and the path length that gets you the concentration of the chemical in the solution. I assume its what you are after. Additional beams are only important if you have interfering chemicals in the solution as well.

Akinrog,

Nitrogen laser has impressive sounding power, but its pulses are less than 10ns long typically. The energy per pulse is very very small. The beam is also virtually impossible to focus, unlike an ordinary laser.


Jack, Red,

UV/Vis spectrometers for me were the dullest things Ive ever used, they tell you virtually nothing about the molecule. Ive heard good things about looking into a glass prism with a telescope for atomic line spectra. CD's dont disperse that cleanly, mainly becuase they arnt straight lines, good enough for working out the frequency of a laser pointer but not much else.

[Marvin]

FUTI,

You are correct but you need to split the laser beam and have a detector on each. One beam has the same in, the other just measures the relative strength of the beam with nothing absorbing. If you know these values and the path length that gets you the concentration of the chemical in the solution. I assume its what you are after. Additional beams are only important if you have interfering chemicals in the solution as well.

Akinrog,

Nitrogen laser has impressive sounding power, but its pulses are less than 10ns long typically. The energy per pulse is very very small. The beam is also virtually impossible to focus, unlike an ordinary laser.


Jack, Red,

UV/Vis spectrometers for me were the dullest things Ive ever used, they tell you virtually nothing about the molecule. Ive heard good things about looking into a glass prism with a telescope for atomic line spectra. CD's dont disperse that cleanly, mainly becuase they arnt straight lines, good enough for working out the frequency of a laser pointer but not much else.

[Jacks Complete]

Marvin,
in the absence of any way to get a diffraction grating, they are about as good as you can get for free. A DVD will have a finer blaze, though. Use the outside edge, and a small peice, with a focusing lens, to get the best results you can. I wouldn't use a glass prism I didn't have a spectra for it for an IR splitter, plus you get pretty poor diffraction angles c.f. a grating.

IR spectroscopy isn't something I've ever really used in anger. You can try to work out the structure of a chemical from it, but these days you are quicker to look it up in a book or database.

The UV pulse isn't hard to focus, just very expensive, needing first surface mirrors or quartz optics! However, the beam is typically fairly parallel, and certainly way above eye-safe levels.

[Jacks Complete]

Marvin,
in the absence of any way to get a diffraction grating, they are about as good as you can get for free. A DVD will have a finer blaze, though. Use the outside edge, and a small peice, with a focusing lens, to get the best results you can. I wouldn't use a glass prism I didn't have a spectra for it for an IR splitter, plus you get pretty poor diffraction angles c.f. a grating.

IR spectroscopy isn't something I've ever really used in anger. You can try to work out the structure of a chemical from it, but these days you are quicker to look it up in a book or database.

The UV pulse isn't hard to focus, just very expensive, needing first surface mirrors or quartz optics! However, the beam is typically fairly parallel, and certainly way above eye-safe levels.

[Jacks Complete]

Marvin,
in the absence of any way to get a diffraction grating, they are about as good as you can get for free. A DVD will have a finer blaze, though. Use the outside edge, and a small peice, with a focusing lens, to get the best results you can. I wouldn't use a glass prism I didn't have a spectra for it for an IR splitter, plus you get pretty poor diffraction angles c.f. a grating.

IR spectroscopy isn't something I've ever really used in anger. You can try to work out the structure of a chemical from it, but these days you are quicker to look it up in a book or database.

The UV pulse isn't hard to focus, just very expensive, needing first surface mirrors or quartz optics! However, the beam is typically fairly parallel, and certainly way above eye-safe levels.

[Marvin]

Edmund scientific and related optics company sell everything from holographic grating film to gold plated ruled masters. CD or DVD maybe free but this is not always value for money. Focusing the light on the grating is completely counter productive, to use a grating the light has to be colamated and the resolution depends on the total area used.

IR spec is useful because it contains so much information, UV/Vis/NIR is next to useless outside specific applications like organometallic chemistry, or working with dyestuffs.

The problem with the N2 laser isnt that its UV, 337nm is fine for ordinary glass its that unlike most lasers it doesnt resonate. Normally you have a low gain medium being pumped between two mirrors, one alowing some laser light through. Aside from being required to lase, this system means that the beam collapses to almost completely parallel - anything off level eventually misses one of the mirrors and nolonger contributes. The nitrogen laser has either 1 or no mirrors, its superradient and self terminating. The result is the very short pulse essentially only has 1 pass (or absolute maximum 2) through the medium. N2 laser pulses just don't focus very well.

The second problem is the energy per pulse is miniscule, an impressive sounding '100 KW' N2 laser may only have half a millijoule of energy in the pulse, the same energy as a 5 mw laser pointer operating for only 1/10th of a second. The peak power is misleading.

As for the whole concept of blinding people with lasers, aside from the seemingly goalless harrassing of the police, assuming someone's eye can be realiably lit with say a 1cm square beam (by the time it reaches the target), that would need a sustained burst of 100mw power just to equal sunlight. I also strongly suspect that the production of that much power would also produce visible results, making who was doing the aiming very clear. Eye response (at very low levels) goes down to longer than 850nm for direct results and high power directly into the eye from 1000nm region and beyond (probably from around 800 to 1400ish) is visible due to doubling effects in the eyeball. This is even assuming the laser produces just the single wavelength with no noise or giveaway flashes of other light..

[Marvin]

Edmund scientific and related optics company sell everything from holographic grating film to gold plated ruled masters. CD or DVD maybe free but this is not always value for money. Focusing the light on the grating is completely counter productive, to use a grating the light has to be colamated and the resolution depends on the total area used.

IR spec is useful because it contains so much information, UV/Vis/NIR is next to useless outside specific applications like organometallic chemistry, or working with dyestuffs.

The problem with the N2 laser isnt that its UV, 337nm is fine for ordinary glass its that unlike most lasers it doesnt resonate. Normally you have a low gain medium being pumped between two mirrors, one alowing some laser light through. Aside from being required to lase, this system means that the beam collapses to almost completely parallel - anything off level eventually misses one of the mirrors and nolonger contributes. The nitrogen laser has either 1 or no mirrors, its superradient and self terminating. The result is the very short pulse essentially only has 1 pass (or absolute maximum 2) through the medium. N2 laser pulses just don't focus very well.

The second problem is the energy per pulse is miniscule, an impressive sounding '100 KW' N2 laser may only have half a millijoule of energy in the pulse, the same energy as a 5 mw laser pointer operating for only 1/10th of a second. The peak power is misleading.

As for the whole concept of blinding people with lasers, aside from the seemingly goalless harrassing of the police, assuming someone's eye can be realiably lit with say a 1cm square beam (by the time it reaches the target), that would need a sustained burst of 100mw power just to equal sunlight. I also strongly suspect that the production of that much power would also produce visible results, making who was doing the aiming very clear. Eye response (at very low levels) goes down to longer than 850nm for direct results and high power directly into the eye from 1000nm region and beyond (probably from around 800 to 1400ish) is visible due to doubling effects in the eyeball. This is even assuming the laser produces just the single wavelength with no noise or giveaway flashes of other light..

[Marvin]

Edmund scientific and related optics company sell everything from holographic grating film to gold plated ruled masters. CD or DVD maybe free but this is not always value for money. Focusing the light on the grating is completely counter productive, to use a grating the light has to be colamated and the resolution depends on the total area used.

IR spec is useful because it contains so much information, UV/Vis/NIR is next to useless outside specific applications like organometallic chemistry, or working with dyestuffs.

The problem with the N2 laser isnt that its UV, 337nm is fine for ordinary glass its that unlike most lasers it doesnt resonate. Normally you have a low gain medium being pumped between two mirrors, one alowing some laser light through. Aside from being required to lase, this system means that the beam collapses to almost completely parallel - anything off level eventually misses one of the mirrors and nolonger contributes. The nitrogen laser has either 1 or no mirrors, its superradient and self terminating. The result is the very short pulse essentially only has 1 pass (or absolute maximum 2) through the medium. N2 laser pulses just don't focus very well.

The second problem is the energy per pulse is miniscule, an impressive sounding '100 KW' N2 laser may only have half a millijoule of energy in the pulse, the same energy as a 5 mw laser pointer operating for only 1/10th of a second. The peak power is misleading.

As for the whole concept of blinding people with lasers, aside from the seemingly goalless harrassing of the police, assuming someone's eye can be realiably lit with say a 1cm square beam (by the time it reaches the target), that would need a sustained burst of 100mw power just to equal sunlight. I also strongly suspect that the production of that much power would also produce visible results, making who was doing the aiming very clear. Eye response (at very low levels) goes down to longer than 850nm for direct results and high power directly into the eye from 1000nm region and beyond (probably from around 800 to 1400ish) is visible due to doubling effects in the eyeball. This is even assuming the laser produces just the single wavelength with no noise or giveaway flashes of other light..

[Jacks Complete]

That's pretty much what I said.

However, if you can get no other grating (due to laws or whatever, and cost, in Bulgaria) it is far better than nothing. As for focusing on the grating, you use a lense to increase the resolution of the grating, by placing it between the detector and the grating. It will probably smooth the output a little, though, unless you get it just right.

NIR is little use, agreed, but that is the only place a homebrewer is going to be able to get a decent shot at making the detectors, optics, etc. work.

As regards the "seeing what you shouldn't", this is true. However, if you get enough light to see the flash from something way down the spectrum, it will be enough energy to blind. Anyone off the axis of the beam won't see the dim flash, since they won't have enough incident energy.

Focusing isn't that hard, since the beam is fairly repeatable from an N2 laser. However, pumping something else (dye lasers) works better, as well as smoothing the pulses.

However, if you want to burn or mark or damage something, the peak energy is what matters. Pulse length makes very little difference, since you are using a high number of high energy photons to put large amounts of power into something in a very short space of time. Don't forget, laser eye damage occurs faster than blink reflex - 5mw for 1/10th of a second is all you would ever get in the visible range, since the target eye would blink. Compress that energy down to a few nanoseconds, and the eye is damaged before the brain even registers the light hitting it. It's like the difference between using a chisel and using a shotgun. The total energy in might be the same, but the results will be very different a lot of the time.

[Jacks Complete]

That's pretty much what I said.

However, if you can get no other grating (due to laws or whatever, and cost, in Bulgaria) it is far better than nothing. As for focusing on the grating, you use a lense to increase the resolution of the grating, by placing it between the detector and the grating. It will probably smooth the output a little, though, unless you get it just right.

NIR is little use, agreed, but that is the only place a homebrewer is going to be able to get a decent shot at making the detectors, optics, etc. work.

As regards the "seeing what you shouldn't", this is true. However, if you get enough light to see the flash from something way down the spectrum, it will be enough energy to blind. Anyone off the axis of the beam won't see the dim flash, since they won't have enough incident energy.

Focusing isn't that hard, since the beam is fairly repeatable from an N2 laser. However, pumping something else (dye lasers) works better, as well as smoothing the pulses.

However, if you want to burn or mark or damage something, the peak energy is what matters. Pulse length makes very little difference, since you are using a high number of high energy photons to put large amounts of power into something in a very short space of time. Don't forget, laser eye damage occurs faster than blink reflex - 5mw for 1/10th of a second is all you would ever get in the visible range, since the target eye would blink. Compress that energy down to a few nanoseconds, and the eye is damaged before the brain even registers the light hitting it. It's like the difference between using a chisel and using a shotgun. The total energy in might be the same, but the results will be very different a lot of the time.

[Jacks Complete]

That's pretty much what I said.

However, if you can get no other grating (due to laws or whatever, and cost, in Bulgaria) it is far better than nothing. As for focusing on the grating, you use a lense to increase the resolution of the grating, by placing it between the detector and the grating. It will probably smooth the output a little, though, unless you get it just right.

NIR is little use, agreed, but that is the only place a homebrewer is going to be able to get a decent shot at making the detectors, optics, etc. work.

As regards the "seeing what you shouldn't", this is true. However, if you get enough light to see the flash from something way down the spectrum, it will be enough energy to blind. Anyone off the axis of the beam won't see the dim flash, since they won't have enough incident energy.

Focusing isn't that hard, since the beam is fairly repeatable from an N2 laser. However, pumping something else (dye lasers) works better, as well as smoothing the pulses.

However, if you want to burn or mark or damage something, the peak energy is what matters. Pulse length makes very little difference, since you are using a high number of high energy photons to put large amounts of power into something in a very short space of time. Don't forget, laser eye damage occurs faster than blink reflex - 5mw for 1/10th of a second is all you would ever get in the visible range, since the target eye would blink. Compress that energy down to a few nanoseconds, and the eye is damaged before the brain even registers the light hitting it. It's like the difference between using a chisel and using a shotgun. The total energy in might be the same, but the results will be very different a lot of the time.

[nbk2000]

When typing up a big reply, always do it in Notepad, or some other text editing program, and save it, prior to attempting to upload the reply to RS.org.

I've been caught out by the 'Disappearing Post' error too, and always after typing out a magnum opus! :( :mad:

[nbk2000]

When typing up a big reply, always do it in Notepad, or some other text editing program, and save it, prior to attempting to upload the reply to RS.org.

I've been caught out by the 'Disappearing Post' error too, and always after typing out a magnum opus! :( :mad:

[nbk2000]

When typing up a big reply, always do it in Notepad, or some other text editing program, and save it, prior to attempting to upload the reply to RS.org.

I've been caught out by the 'Disappearing Post' error too, and always after typing out a magnum opus! :( :mad:

[FUTI]

to Jack's Complete: As "homebrewer" I'm interested in anything even NIR although I have no use of it right now (but I can try to watch the clouds in NIR just for fun:)). So if you have idea how to do it I can try it. You can PM to me.

to Marvin: I will certainly try prism, but CD is good idea (I give it a try just for fun). I wanted to split beam anyway due to power oscillation (I love electrical company:(). I have question. I was taught that "semipermeable mirror" is best way to do that. I know that it can be achieved with prisms too. Obviously I will have to go with prism and a ordinary mirror because I don't have semipermeable mirror. Why is first design better?

Simly RED I see what are you cooking:D? But I think you are on wrong tracks. There were speculations about Russians used MW in that Moscow theatre terrorist incident, but I think that is a hoax and demonstration of good old CW in action. CW has one benefit over MW, easier to control and can be directed to some extent due to concentration dependence on action. To do that with MW you would have to have mean to make directed beam (focal point) on target which is hard. I think that action of MW isn't neurotransmitter related, but some way of neuronal membrane disturbation. Good choice of neurotransmitter though since if you make GABA receptor fault since they work as inhibitory it makes sympthoms similar to seisure (epilepsy?).

akinrog that link is very good, you always suprise me with ideas and knowledge you have. Thanks.

[FUTI]

to Jack's Complete: As "homebrewer" I'm interested in anything even NIR although I have no use of it right now (but I can try to watch the clouds in NIR just for fun:)). So if you have idea how to do it I can try it. You can PM to me.

to Marvin: I will certainly try prism, but CD is good idea (I give it a try just for fun). I wanted to split beam anyway due to power oscillation (I love electrical company:(). I have question. I was taught that "semipermeable mirror" is best way to do that. I know that it can be achieved with prisms too. Obviously I will have to go with prism and a ordinary mirror because I don't have semipermeable mirror. Why is first design better?

Simly RED I see what are you cooking:D? But I think you are on wrong tracks. There were speculations about Russians used MW in that Moscow theatre terrorist incident, but I think that is a hoax and demonstration of good old CW in action. CW has one benefit over MW, easier to control and can be directed to some extent due to concentration dependence on action. To do that with MW you would have to have mean to make directed beam (focal point) on target which is hard. I think that action of MW isn't neurotransmitter related, but some way of neuronal membrane disturbation. Good choice of neurotransmitter though since if you make GABA receptor fault since they work as inhibitory it makes sympthoms similar to seisure (epilepsy?).

akinrog that link is very good, you always suprise me with ideas and knowledge you have. Thanks.

[FUTI]

to Jack's Complete: As "homebrewer" I'm interested in anything even NIR although I have no use of it right now (but I can try to watch the clouds in NIR just for fun:)). So if you have idea how to do it I can try it. You can PM to me.

to Marvin: I will certainly try prism, but CD is good idea (I give it a try just for fun). I wanted to split beam anyway due to power oscillation (I love electrical company:(). I have question. I was taught that "semipermeable mirror" is best way to do that. I know that it can be achieved with prisms too. Obviously I will have to go with prism and a ordinary mirror because I don't have semipermeable mirror. Why is first design better?

Simly RED I see what are you cooking:D? But I think you are on wrong tracks. There were speculations about Russians used MW in that Moscow theatre terrorist incident, but I think that is a hoax and demonstration of good old CW in action. CW has one benefit over MW, easier to control and can be directed to some extent due to concentration dependence on action. To do that with MW you would have to have mean to make directed beam (focal point) on target which is hard. I think that action of MW isn't neurotransmitter related, but some way of neuronal membrane disturbation. Good choice of neurotransmitter though since if you make GABA receptor fault since they work as inhibitory it makes sympthoms similar to seisure (epilepsy?).

akinrog that link is very good, you always suprise me with ideas and knowledge you have. Thanks.

[simply RED]

What about dye lasers?

I read about it in the book:
" Manual for theory and practice of lasers " 1996: "University publishment" .
The book contained some extremely complex shemes of such lasers.
Is there a way to make such laser with a normal "easy" scheme?

The manual also contained schemes of almost every possible laser invented so far.
Only diode pumped could be made hand held. (also see the new diodes... 50W in IR and above)

In order to make high power one, you need CO2 or chemical laser (F2, D2).
To illuminate in UV with high power - you need eximeric laser.

The other good use of a laser is a part of a remote control. Reliable. Quite easier to make than radio, cheaper, so you could "sacrifice" the receiver.

http://technology.niagarac.on.ca/people/mcsele/lasers/LasersOther.htm

The diagram shows how to amplitude modulate a diode.
(extremely good link, akinrog)

FUTI, I recently work on multiple "projects" at once. You never know which one will finally come to realisation. Of course this is a joke compared to VXs for example...

[simply RED]

What about dye lasers?

I read about it in the book:
" Manual for theory and practice of lasers " 1996: "University publishment" .
The book contained some extremely complex shemes of such lasers.
Is there a way to make such laser with a normal "easy" scheme?

The manual also contained schemes of almost every possible laser invented so far.
Only diode pumped could be made hand held. (also see the new diodes... 50W in IR and above)

In order to make high power one, you need CO2 or chemical laser (F2, D2).
To illuminate in UV with high power - you need eximeric laser.

The other good use of a laser is a part of a remote control. Reliable. Quite easier to make than radio, cheaper, so you could "sacrifice" the receiver.

http://technology.niagarac.on.ca/people/mcsele/lasers/LasersOther.htm

The diagram shows how to amplitude modulate a diode.
(extremely good link, akinrog)

FUTI, I recently work on multiple "projects" at once. You never know which one will finally come to realisation. Of course this is a joke compared to VXs for example...

[simply RED]

What about dye lasers?

I read about it in the book:
" Manual for theory and practice of lasers " 1996: "University publishment" .
The book contained some extremely complex shemes of such lasers.
Is there a way to make such laser with a normal "easy" scheme?

The manual also contained schemes of almost every possible laser invented so far.
Only diode pumped could be made hand held. (also see the new diodes... 50W in IR and above)

In order to make high power one, you need CO2 or chemical laser (F2, D2).
To illuminate in UV with high power - you need eximeric laser.

The other good use of a laser is a part of a remote control. Reliable. Quite easier to make than radio, cheaper, so you could "sacrifice" the receiver.

http://technology.niagarac.on.ca/people/mcsele/lasers/LasersOther.htm

The diagram shows how to amplitude modulate a diode.
(extremely good link, akinrog)

FUTI, I recently work on multiple "projects" at once. You never know which one will finally come to realisation. Of course this is a joke compared to VXs for example...

[kingspaz]

Heres a little about chemical oxygen-iodine lasers (COIL).

http://www.afrlhorizons.com/Briefs/Dec01/DE0104.html

[kingspaz]

Heres a little about chemical oxygen-iodine lasers (COIL).

http://www.afrlhorizons.com/Briefs/Dec01/DE0104.html

[kingspaz]

Heres a little about chemical oxygen-iodine lasers (COIL).

http://www.afrlhorizons.com/Briefs/Dec01/DE0104.html

[Jacks Complete]

COIL are cool. A stunning amount of power out, considering the mass in. In use for the Boeing Anti-Ballistic Missile airplane project (I forget the name)

FEL is the best, though, using nothing but electricity.

The Isreali army built a laser system that uses burning petrol as the laser medium, which is also very smart.

FUTI:
For an easy beam splitter, you can use a microwave slide at an angle, or even, for low powers, cling film. The thiner the material the better. Also, an unburned section of CD will split a beam quite a lot, but the other way. You can get mylar film in various thicknesses, too, but that's harder to get (try a silver foil survival blanket)

======\-------
|
|

EDIT: Marvin, following on from the vbChat, I suggest you look at "laser damage mechanisms" on google, for more info.

http://www.tecoptics.com/laseroptics/threshold.htm says, for example,
Laser Damage Threshold Mechanisms
With the ever-increasing laser peak powers and pulse energies that are now attainable, laser coating technology must similarly improve. A number of mechanisms cause laser coating failure. The most important are absorption and electron avalanche.

Absorption causes thermal laser damage. Bulk absorption can be avoided by the choice of non-absorbing materials and by making sure all materials are of the highest quality with no absorbing impurities. Localized absorption can come from inclusions in the coating (prevented by appropriate coating techniques) or from surface-absorbed contaminants.

Electron-avalanche induced damage comes from multiphoton absorption that ionizes the material, causing shock waves and vaporization. The damage can occur in surface imperfections, in one of the dielectric materials, or at the interface between materials. Since the processes are multi-photon, the probability of damage increases very non-linearly with laser power density (normally expressed in watts/cm2).

Note that non-linear effects are more likely at higher powers, and duration has little to do with it, as they tend to be things like photon interactions, multiple absorptions, etc. so higher peak powers, even though a lower total energy, have far more effect. Hence the use of Q-switching and other pulse compression techniques.

[Jacks Complete]

COIL are cool. A stunning amount of power out, considering the mass in. In use for the Boeing Anti-Ballistic Missile airplane project (I forget the name)

FEL is the best, though, using nothing but electricity.

The Isreali army built a laser system that uses burning petrol as the laser medium, which is also very smart.

FUTI:
For an easy beam splitter, you can use a microwave slide at an angle, or even, for low powers, cling film. The thiner the material the better. Also, an unburned section of CD will split a beam quite a lot, but the other way. You can get mylar film in various thicknesses, too, but that's harder to get (try a silver foil survival blanket)

======\-------
|
|

EDIT: Marvin, following on from the vbChat, I suggest you look at "laser damage mechanisms" on google, for more info.

http://www.tecoptics.com/laseroptics/threshold.htm says, for example,
Laser Damage Threshold Mechanisms
With the ever-increasing laser peak powers and pulse energies that are now attainable, laser coating technology must similarly improve. A number of mechanisms cause laser coating failure. The most important are absorption and electron avalanche.

Absorption causes thermal laser damage. Bulk absorption can be avoided by the choice of non-absorbing materials and by making sure all materials are of the highest quality with no absorbing impurities. Localized absorption can come from inclusions in the coating (prevented by appropriate coating techniques) or from surface-absorbed contaminants.

Electron-avalanche induced damage comes from multiphoton absorption that ionizes the material, causing shock waves and vaporization. The damage can occur in surface imperfections, in one of the dielectric materials, or at the interface between materials. Since the processes are multi-photon, the probability of damage increases very non-linearly with laser power density (normally expressed in watts/cm2).

Note that non-linear effects are more likely at higher powers, and duration has little to do with it, as they tend to be things like photon interactions, multiple absorptions, etc. so higher peak powers, even though a lower total energy, have far more effect. Hence the use of Q-switching and other pulse compression techniques.

[Jacks Complete]

COIL are cool. A stunning amount of power out, considering the mass in. In use for the Boeing Anti-Ballistic Missile airplane project (I forget the name)

FEL is the best, though, using nothing but electricity.

The Isreali army built a laser system that uses burning petrol as the laser medium, which is also very smart.

FUTI:
For an easy beam splitter, you can use a microwave slide at an angle, or even, for low powers, cling film. The thiner the material the better. Also, an unburned section of CD will split a beam quite a lot, but the other way. You can get mylar film in various thicknesses, too, but that's harder to get (try a silver foil survival blanket)

======\-------
|
|

EDIT: Marvin, following on from the vbChat, I suggest you look at "laser damage mechanisms" on google, for more info.

http://www.tecoptics.com/laseroptics/threshold.htm says, for example,
Laser Damage Threshold Mechanisms
With the ever-increasing laser peak powers and pulse energies that are now attainable, laser coating technology must similarly improve. A number of mechanisms cause laser coating failure. The most important are absorption and electron avalanche.

Absorption causes thermal laser damage. Bulk absorption can be avoided by the choice of non-absorbing materials and by making sure all materials are of the highest quality with no absorbing impurities. Localized absorption can come from inclusions in the coating (prevented by appropriate coating techniques) or from surface-absorbed contaminants.

Electron-avalanche induced damage comes from multiphoton absorption that ionizes the material, causing shock waves and vaporization. The damage can occur in surface imperfections, in one of the dielectric materials, or at the interface between materials. Since the processes are multi-photon, the probability of damage increases very non-linearly with laser power density (normally expressed in watts/cm2).

Note that non-linear effects are more likely at higher powers, and duration has little to do with it, as they tend to be things like photon interactions, multiple absorptions, etc. so higher peak powers, even though a lower total energy, have far more effect. Hence the use of Q-switching and other pulse compression techniques.

[cougar98332]

a powerful laser is goin to get get rather hot, so even pumping enough power into the little laser wont do any good as it would overheat. you have the righ right optics, proper circuitry, and a cooling system, if you are really interested in laser building then i suggest visiting: http://technology.niagarac.on.ca/people/mcsele/lasers/index.html

[cougar98332]

a powerful laser is goin to get get rather hot, so even pumping enough power into the little laser wont do any good as it would overheat. you have the righ right optics, proper circuitry, and a cooling system, if you are really interested in laser building then i suggest visiting: http://technology.niagarac.on.ca/people/mcsele/lasers/index.html

[Marvin]

Jack,

That is for laser coatings, dichroic mirrors, transparent films, frequency multipliers/mixers and so on, it has nothing at all to do with biological systems.

Since you bring up the topic of threshold damage, which is easier to obtain data for, it seems reasonable to accept the limiting powers of eye safe lasers (class 1) as relavent. In the visible range, for pulsed lasers the limits are between about 4e-6 and 2e-7 Joules. Whats most obvious though, is that the longest pulse, 1ms corrispond to the highest power, as expected, but the step up to 1us pulses, 3 orders of magnetude increase in *peak power* gets a decrease of only 1 order of magnetude reduction in pulse energy. When you move right the way to pulses of duration 10 or 20ns, ie a furthur 2 orders of magnetude increase in *peak power* there is no change at all in allowed pulse energy. This does not corrispond at all with increases in peak power being related to eye damage. It makes far more sense to think in terms of a time frame, from the numbers in the region of 100us seems about right within which total energy is what sets the threshold for damage and it being completely useless to talk about peak power.

The free electron laser is a waste of time, while it uses no chemicals this is a disadvantage given power densities of chemicals versus batteries and capacitors. Its also less a discrete tool and more a set of magnets you attach to someone elses synchotron.

[Marvin]

Jack,

That is for laser coatings, dichroic mirrors, transparent films, frequency multipliers/mixers and so on, it has nothing at all to do with biological systems.

Since you bring up the topic of threshold damage, which is easier to obtain data for, it seems reasonable to accept the limiting powers of eye safe lasers (class 1) as relavent. In the visible range, for pulsed lasers the limits are between about 4e-6 and 2e-7 Joules. Whats most obvious though, is that the longest pulse, 1ms corrispond to the highest power, as expected, but the step up to 1us pulses, 3 orders of magnetude increase in *peak power* gets a decrease of only 1 order of magnetude reduction in pulse energy. When you move right the way to pulses of duration 10 or 20ns, ie a furthur 2 orders of magnetude increase in *peak power* there is no change at all in allowed pulse energy. This does not corrispond at all with increases in peak power being related to eye damage. It makes far more sense to think in terms of a time frame, from the numbers in the region of 100us seems about right within which total energy is what sets the threshold for damage and it being completely useless to talk about peak power.

The free electron laser is a waste of time, while it uses no chemicals this is a disadvantage given power densities of chemicals versus batteries and capacitors. Its also less a discrete tool and more a set of magnets you attach to someone elses synchotron.

[Jacks Complete]

If you are using an FEL at "home" they are great, since you just run them via the socket, and turn them to the frequency you want. However, you are right that for portable purposes they are useless.

As for the laser threshold damage thing, yes, once you get down to the tiny, tiny pulse lengths, you get other effects. For one thing, very short pulses tend to get spread out by most coated optics, since they do strange things as they pass through. I seriously doubt you could get a 10ns or shorter pulse to the back of the eye, as it would spread in length/time as it traveled through the cornea, lens, fluid, etc.

From what you quote, it sounds like the laser damage mechanisms for eye safe pulsed lasers are fairly high, then. This explains how the army can use high powered long range, yet eye safe laser designators. However, dropping from a 1ms pulse to a 1us pulse means you have to drop your peak power to 10% to remain eye-safe. So if you take your 1ms pulse and compress it down to 1us, you will have a peak power of (at 100% eff.) 100 times your previous peak power level, yet this leaves it 1000 times more powerful than the limits for eye-safety.

So I am right. If you compress your pulses down, you are more likely to be able to use them for a blinding device, for the same electrical power in. Instead of a steady CW beam at 1mW (or, more usefully here, 1mJ/s), which is eye safe, you could easily have a peak power of 1W from that same power, in 1ms per second, or a pulse power of 1mJ, which is far beyond the eye safe limit of 4uJ. Further compression to a 1us pulse would yeild a peak power of 1kW, with the same 1mJ power, whilst the eye safe limit at that level would drop to 10% of the limit for the longer pulse, presumably 0.4uJ.

So at a 1ms pulse length, a 1mJ peak is 250 times the eye safe limit, while at 1us pulse length, it is 2500 times the eye safe limit, using the data you provided. This would be like carrying a 2.5W CW laser with you!

Now consider that we can get about 50mW of CW power, and that would, with compression, give a nominal level of 12500 times the eyesafe level at 1ms. Let's compress it further, but fire it ten times a second, rather than once, and we get the same result.

Assume we loose 50% doing the compression, and that leaves us with a laser pen that is firing 10 times a second with the equivalent power of a 6.25W laser!

[Jacks Complete]

If you are using an FEL at "home" they are great, since you just run them via the socket, and turn them to the frequency you want. However, you are right that for portable purposes they are useless.

As for the laser threshold damage thing, yes, once you get down to the tiny, tiny pulse lengths, you get other effects. For one thing, very short pulses tend to get spread out by most coated optics, since they do strange things as they pass through. I seriously doubt you could get a 10ns or shorter pulse to the back of the eye, as it would spread in length/time as it traveled through the cornea, lens, fluid, etc.

From what you quote, it sounds like the laser damage mechanisms for eye safe pulsed lasers are fairly high, then. This explains how the army can use high powered long range, yet eye safe laser designators. However, dropping from a 1ms pulse to a 1us pulse means you have to drop your peak power to 10% to remain eye-safe. So if you take your 1ms pulse and compress it down to 1us, you will have a peak power of (at 100% eff.) 100 times your previous peak power level, yet this leaves it 1000 times more powerful than the limits for eye-safety.

So I am right. If you compress your pulses down, you are more likely to be able to use them for a blinding device, for the same electrical power in. Instead of a steady CW beam at 1mW (or, more usefully here, 1mJ/s), which is eye safe, you could easily have a peak power of 1W from that same power, in 1ms per second, or a pulse power of 1mJ, which is far beyond the eye safe limit of 4uJ. Further compression to a 1us pulse would yeild a peak power of 1kW, with the same 1mJ power, whilst the eye safe limit at that level would drop to 10% of the limit for the longer pulse, presumably 0.4uJ.

So at a 1ms pulse length, a 1mJ peak is 250 times the eye safe limit, while at 1us pulse length, it is 2500 times the eye safe limit, using the data you provided. This would be like carrying a 2.5W CW laser with you!

Now consider that we can get about 50mW of CW power, and that would, with compression, give a nominal level of 12500 times the eyesafe level at 1ms. Let's compress it further, but fire it ten times a second, rather than once, and we get the same result.

Assume we loose 50% doing the compression, and that leaves us with a laser pen that is firing 10 times a second with the equivalent power of a 6.25W laser!

[Marvin]

"If you are using an FEL at "home" they are great, since you just run them via the socket,"

Well, Hmm, you run the accelerator probably from industrial 3 phase mains and that might involve some sort of socket....

"For one thing, very short pulses tend to get spread out by most coated optics, since they do strange things as they pass through. I seriously doubt you could get a 10ns or shorter pulse to the back of the eye, as it would spread in length/time as it traveled through the cornea, lens, fluid, etc. "

I can see where this concept is coming from, you are thinking of pulses speading out like ripples on water. The problem you have here is that 10ns amounts to a 3 meter long light pulse (in air) and significant spreading by a few cm of transparent material is quite obviously not going to happen. If the pulse were in the femotosecond range you might have a case.

"it sounds like the laser damage mechanisms for eye safe pulsed lasers are fairly high, then"

I dont follow.

"This explains how the army can use high powered long range, yet eye safe laser designators. "

The army rangefinders tend to use intrinsically eye safe wavelengths that never reach the retina, damage thresholds are then many orders of magnetude higher.

"However, dropping from a 1ms pulse to a 1us pulse means you have to drop your peak power to 10% to remain eye-safe. So if you take your 1ms pulse and compress it down to 1us, you will have a peak power of (at 100% eff.) 100 times your previous peak power level, yet this leaves it 1000 times more powerful than the limits for eye-safety."

There are several ways to interpret this, as far as I can determine they are all wrong. The limits deal with total pulse energy for given values of pulse length. Peak power is not relavent, trying to convert between is just going to confuse everyone.

"So I am right. If you compress your pulses down, you are more likely to be able to use them for a blinding device"

You are more likley to exceed damage threshold levels, I'm not sure thats quite the same thing. If you take energy over a long period and release it in a short period it will usually do more damage, I dont think this was ever in doubt. The issue as far as I was aware concerned the peak power of very short pulse devices like the N2 laser and if these numbers had any real meaning in the context of eye safety. I think I've shown they don't.

"So at a 1ms pulse length, a 1mJ peak is 250 times the eye safe limit, while at 1us pulse length, it is 2500 times the eye safe limit, using the data you provided. "

If you remove the word 'peak' then that looks in the right ball park. Having said that what are we supposed to assume by 250 and 2500 times? Should we be impressed? Are we to assume this is eclipse without sunglasses territory or Exodos in Oedipus Rex? As far as the ANSI standard goes its if you exceed the numbers, not by how much.

"This would be like carrying a 2.5W CW laser with you!"

Huh?

"Now consider that we can get about 50mW of CW power, and that would, with compression, give a nominal level of 12500 times the eyesafe level at 1ms. Let's compress it further, but fire it ten times a second, rather than once, and we get the same result."

So far you seem to be taking numbers that sound reasonable, in order to turn them into numbers that sound impressesive without any real thought to how feasable it actually is. For example, you seem to be using an unstated value of 1 second pulse length for all your math. Why 1? Why not an hour? Why not a day? Why not the full 6000 hours average lifespan of the core diode? Are you just confusing energy with power? You are also equating multiple pulses with combined damage thresholds.

The last bit is noteworthy because it moves from highly questionable feasability to outright self delusion. If you take a 50mw pointer, and compress an entire second into a short pulse - and then fire it 10 times a second, you are by definition expecting 500mw average power. For a laser diode designed specifically for pulsing I would expect a several fold increase in allowed power levels for a short pulse over CW - at much reduced average power. This would be somewhat short of the 6 orders of magnetude you seem to be expecting. Other forms of laser will have limits with different causes but similar conclusions.

[Marvin]

"If you are using an FEL at "home" they are great, since you just run them via the socket,"

Well, Hmm, you run the accelerator probably from industrial 3 phase mains and that might involve some sort of socket....

"For one thing, very short pulses tend to get spread out by most coated optics, since they do strange things as they pass through. I seriously doubt you could get a 10ns or shorter pulse to the back of the eye, as it would spread in length/time as it traveled through the cornea, lens, fluid, etc. "

I can see where this concept is coming from, you are thinking of pulses speading out like ripples on water. The problem you have here is that 10ns amounts to a 3 meter long light pulse (in air) and significant spreading by a few cm of transparent material is quite obviously not going to happen. If the pulse were in the femotosecond range you might have a case.

"it sounds like the laser damage mechanisms for eye safe pulsed lasers are fairly high, then"

I dont follow.

"This explains how the army can use high powered long range, yet eye safe laser designators. "

The army rangefinders tend to use intrinsically eye safe wavelengths that never reach the retina, damage thresholds are then many orders of magnetude higher.

"However, dropping from a 1ms pulse to a 1us pulse means you have to drop your peak power to 10% to remain eye-safe. So if you take your 1ms pulse and compress it down to 1us, you will have a peak power of (at 100% eff.) 100 times your previous peak power level, yet this leaves it 1000 times more powerful than the limits for eye-safety."

There are several ways to interpret this, as far as I can determine they are all wrong. The limits deal with total pulse energy for given values of pulse length. Peak power is not relavent, trying to convert between is just going to confuse everyone.

"So I am right. If you compress your pulses down, you are more likely to be able to use them for a blinding device"

You are more likley to exceed damage threshold levels, I'm not sure thats quite the same thing. If you take energy over a long period and release it in a short period it will usually do more damage, I dont think this was ever in doubt. The issue as far as I was aware concerned the peak power of very short pulse devices like the N2 laser and if these numbers had any real meaning in the context of eye safety. I think I've shown they don't.

"So at a 1ms pulse length, a 1mJ peak is 250 times the eye safe limit, while at 1us pulse length, it is 2500 times the eye safe limit, using the data you provided. "

If you remove the word 'peak' then that looks in the right ball park. Having said that what are we supposed to assume by 250 and 2500 times? Should we be impressed? Are we to assume this is eclipse without sunglasses territory or Exodos in Oedipus Rex? As far as the ANSI standard goes its if you exceed the numbers, not by how much.

"This would be like carrying a 2.5W CW laser with you!"

Huh?

"Now consider that we can get about 50mW of CW power, and that would, with compression, give a nominal level of 12500 times the eyesafe level at 1ms. Let's compress it further, but fire it ten times a second, rather than once, and we get the same result."

So far you seem to be taking numbers that sound reasonable, in order to turn them into numbers that sound impressesive without any real thought to how feasable it actually is. For example, you seem to be using an unstated value of 1 second pulse length for all your math. Why 1? Why not an hour? Why not a day? Why not the full 6000 hours average lifespan of the core diode? Are you just confusing energy with power? You are also equating multiple pulses with combined damage thresholds.

The last bit is noteworthy because it moves from highly questionable feasability to outright self delusion. If you take a 50mw pointer, and compress an entire second into a short pulse - and then fire it 10 times a second, you are by definition expecting 500mw average power. For a laser diode designed specifically for pulsing I would expect a several fold increase in allowed power levels for a short pulse over CW - at much reduced average power. This would be somewhat short of the 6 orders of magnetude you seem to be expecting. Other forms of laser will have limits with different causes but similar conclusions.

[Jacks Complete]

Ok, I never said that compressing the pulse from a standard laser diode was going to be trivial. The fact that it is, is neither here nor there.

It is a fact that you can get sharp, high power pulses from diode lasers. This will not work from a DPSS laser, but will with a bare diode.

It is also a fact that the shorter, higher energy pulses damage the eye whilst requiring a lot less electrical energy in.

Now for a portable weapon, you will not be able to run a 5W weapon for long off a battery, and a pair of AA batteries would last for a few seconds CW.

So, what we do is we turn the laser on at those powers for very short times, in the order of tenths or less of a second. The shorter the pulse, to an extent, the more energy you can pour into it without burning out the laser diode, and the longer the batteries will last. This is called the Duty Cycle.

"So at a 1ms pulse length, a 1mJ peak is 250 times the eye safe limit, while at 1us pulse length, it is 2500 times the eye safe limit, using the data you provided. "

If you remove the word 'peak' then that looks in the right ball park.

Yes, you could wrongly remove the word "peak". However, given that you will be switching the laser quite quickly, you will be biasing the voltage in the regular way, and holding it just below threshold for the duration of the string of pulses, as this ensures a faster response from the laser, and stops transients from reversing the voltage across the junction, killing the diode. Given this, you will have a beam of microwatts punctuated by pulses of far higher power.

If you want to know if pulse compression works, go read about industry cutting diodes. They run at higher powers, using arrays, heavy cooling and pulses! They are pulsed very fast, at quite a high duty cycle, but the reason they are pulsed is mostly to do with the higher peak power to the target, which causes more heat at the target, causing rapid thermal effects, and blowing small holes all the way along, rather than a slow melting.

Compare a 3 bar electric fire with a cutting laser at 3kW input power. You get about the same effective heat out of both, but the CO2 runs at about 40% efficiency. So you get a nice beam for cutting things. You focus this down to a small spot, and cut with it. You also focus it in time. More energy arriving per unit time does more damage. The 3 bar fire is never, ever going to melt the steel plate. The 3kW laser as CW is going to warm it enough for welding, perhaps. Turned into a 10% duty cycle throwing out 30kW in 10% of the time (yes, I know the units are wrong at this stage - it is a 30kJ pulse) causes far more energy absorption at the target, which boils it instantly, and it explosively boils away. This expansion is massive damage in anything that will not withstand well a sudden high pressure event.

Take a look at http://www.sslasers.com/Laser_Diode_Arrays.htm - every one of the arrays on there are 10% duty cycle pulsed diode arrays. Hunt around. All the highest power diodes are pulsed, and they are used for cutting and welding. If they got the same results from a DC laser, why mess about making a pulsed one?

Should we be impressed? Are we to assume this is eclipse without sunglasses territory or Exodos in Oedipus Rex? As far as the ANSI standard goes its if you exceed the numbers, not by how much.You are seriously telling me that you think that exceeding is the only target? So you get hit by a megajoule pulse, and you think it would do the same eye damage as a 10mW CW laser because it is a few nanoseconds? Are you winding me up?

So far you seem to be taking numbers that sound reasonable, in order to turn them into numbers that sound impressesive without any real thought to how feasable it actually is. For example, you seem to be using an unstated value of 1 second pulse length for all your math. Why 1?
Because 1W == 1J/s, of course.

Why not an hour? Why not a day? Why not the full 6000 hours average lifespan of the core diode? Because a Q-switch or other pulse compressor to do that has yet to be invented.
Are you just confusing energy with power? You are also equating multiple pulses with combined damage thresholds.No, I'm not. I am stating a well known fact. A short high power pulse does more damage than the same energy spread out. This is right, it is common knowledge, and it tallies with normal life. If I accelerate your body with a short pulse (1ms) of power at 1000m/s, you are dead, even if you only wind up moving at 1m/s. A 10m/s acceleration for 1 second would leave you at 10 m/s, but alive.

The last bit is noteworthy because it moves from highly questionable feasability to outright self delusion. If you take a 50mw pointer, and compress an entire second into a short pulse - and then fire it 10 times a second, you are by definition expecting 500mw average power. That's why I say "Let's compress it further, but fire it ten times a second, rather than once, and we get the same result." Obviously I was talking about keeping the same average power.

For a laser diode designed specifically for pulsing I would expect a several fold increase in allowed power levels for a short pulse over CW - at much reduced average power. This would be somewhat short of the 6 orders of magnitude you seem to be expecting. Other forms of laser will have limits with different causes but similar conclusions.

The last bit is not noteworthy for being wrong. It is correct. You take the nominal maximum CW power for the diode, say 50mW, and you turn it into a set of compressed pulses, for the reasons above. The higher energy per unit time, which gives us an indication of the damage to target from the figures you gave for eye-safe beams, shows that this is a more effective way to damage the eye. In fact, if you cut your pulses down to what you state is the most damaging band, you will save a lot of energy.

Yes, the diode gets less efficient at higher pulse powers and shorter pulse times. You need to select your diode for this application. However, you might be using a dye saturation Q switch, or a mode-locked laser, or a chirped pulse compression fibre, or whatever, running off a CW laser of almost any type.

However, compressing the pulse from CW down to higher (peak pulse) powers works. Industry do it all the time. There is a hell of a lot of research into it, too. http://physics.unr.edu/grad/aguilar/presentation/physics709fall01.pdf is a fairly good paper on it.

[Jacks Complete]

Ok, I never said that compressing the pulse from a standard laser diode was going to be trivial. The fact that it is, is neither here nor there.

It is a fact that you can get sharp, high power pulses from diode lasers. This will not work from a DPSS laser, but will with a bare diode.

It is also a fact that the shorter, higher energy pulses damage the eye whilst requiring a lot less electrical energy in.

Now for a portable weapon, you will not be able to run a 5W weapon for long off a battery, and a pair of AA batteries would last for a few seconds CW.

So, what we do is we turn the laser on at those powers for very short times, in the order of tenths or less of a second. The shorter the pulse, to an extent, the more energy you can pour into it without burning out the laser diode, and the longer the batteries will last. This is called the Duty Cycle.

"So at a 1ms pulse length, a 1mJ peak is 250 times the eye safe limit, while at 1us pulse length, it is 2500 times the eye safe limit, using the data you provided. "

If you remove the word 'peak' then that looks in the right ball park.

Yes, you could wrongly remove the word "peak". However, given that you will be switching the laser quite quickly, you will be biasing the voltage in the regular way, and holding it just below threshold for the duration of the string of pulses, as this ensures a faster response from the laser, and stops transients from reversing the voltage across the junction, killing the diode. Given this, you will have a beam of microwatts punctuated by pulses of far higher power.

If you want to know if pulse compression works, go read about industry cutting diodes. They run at higher powers, using arrays, heavy cooling and pulses! They are pulsed very fast, at quite a high duty cycle, but the reason they are pulsed is mostly to do with the higher peak power to the target, which causes more heat at the target, causing rapid thermal effects, and blowing small holes all the way along, rather than a slow melting.

Compare a 3 bar electric fire with a cutting laser at 3kW input power. You get about the same effective heat out of both, but the CO2 runs at about 40% efficiency. So you get a nice beam for cutting things. You focus this down to a small spot, and cut with it. You also focus it in time. More energy arriving per unit time does more damage. The 3 bar fire is never, ever going to melt the steel plate. The 3kW laser as CW is going to warm it enough for welding, perhaps. Turned into a 10% duty cycle throwing out 30kW in 10% of the time (yes, I know the units are wrong at this stage - it is a 30kJ pulse) causes far more energy absorption at the target, which boils it instantly, and it explosively boils away. This expansion is massive damage in anything that will not withstand well a sudden high pressure event.

Take a look at http://www.sslasers.com/Laser_Diode_Arrays.htm - every one of the arrays on there are 10% duty cycle pulsed diode arrays. Hunt around. All the highest power diodes are pulsed, and they are used for cutting and welding. If they got the same results from a DC laser, why mess about making a pulsed one?

Should we be impressed? Are we to assume this is eclipse without sunglasses territory or Exodos in Oedipus Rex? As far as the ANSI standard goes its if you exceed the numbers, not by how much.You are seriously telling me that you think that exceeding is the only target? So you get hit by a megajoule pulse, and you think it would do the same eye damage as a 10mW CW laser because it is a few nanoseconds? Are you winding me up?

So far you seem to be taking numbers that sound reasonable, in order to turn them into numbers that sound impressesive without any real thought to how feasable it actually is. For example, you seem to be using an unstated value of 1 second pulse length for all your math. Why 1?
Because 1W == 1J/s, of course.

Why not an hour? Why not a day? Why not the full 6000 hours average lifespan of the core diode? Because a Q-switch or other pulse compressor to do that has yet to be invented.
Are you just confusing energy with power? You are also equating multiple pulses with combined damage thresholds.No, I'm not. I am stating a well known fact. A short high power pulse does more damage than the same energy spread out. This is right, it is common knowledge, and it tallies with normal life. If I accelerate your body with a short pulse (1ms) of power at 1000m/s, you are dead, even if you only wind up moving at 1m/s. A 10m/s acceleration for 1 second would leave you at 10 m/s, but alive.

The last bit is noteworthy because it moves from highly questionable feasability to outright self delusion. If you take a 50mw pointer, and compress an entire second into a short pulse - and then fire it 10 times a second, you are by definition expecting 500mw average power. That's why I say "Let's compress it further, but fire it ten times a second, rather than once, and we get the same result." Obviously I was talking about keeping the same average power.

For a laser diode designed specifically for pulsing I would expect a several fold increase in allowed power levels for a short pulse over CW - at much reduced average power. This would be somewhat short of the 6 orders of magnitude you seem to be expecting. Other forms of laser will have limits with different causes but similar conclusions.

The last bit is not noteworthy for being wrong. It is correct. You take the nominal maximum CW power for the diode, say 50mW, and you turn it into a set of compressed pulses, for the reasons above. The higher energy per unit time, which gives us an indication of the damage to target from the figures you gave for eye-safe beams, shows that this is a more effective way to damage the eye. In fact, if you cut your pulses down to what you state is the most damaging band, you will save a lot of energy.

Yes, the diode gets less efficient at higher pulse powers and shorter pulse times. You need to select your diode for this application. However, you might be using a dye saturation Q switch, or a mode-locked laser, or a chirped pulse compression fibre, or whatever, running off a CW laser of almost any type.

However, compressing the pulse from CW down to higher (peak pulse) powers works. Industry do it all the time. There is a hell of a lot of research into it, too. http://physics.unr.edu/grad/aguilar/presentation/physics709fall01.pdf is a fairly good paper on it.

[Marvin]

"Ok, I never said that compressing the pulse from a standard laser diode was going to be trivial. "

I agree, in fact you havn't provided any evidence it can be done at all. Its a little like working out the maths for killing people by making all the hydrogen atoms in their body fuse to helium. Even if you get the maths right, you are still no closer to actually doing it.

"It is a fact that you can get sharp, high power pulses from diode lasers. "

How sharp, 1 second? 1 nanosecond? What diode lasers? How high a power? This is a meaningless statement without numbers let alone an actual 'fact'. In addition 'high power' is not a useful term as Ive allready shown, with or without numbers.

"It is also a fact that the shorter, higher energy pulses damage the eye whilst requiring a lot less electrical energy in."

Another 'fact', how much shorter? How much higher? How much damage? How much less energy in?
But wait, Ive already provided examples of that information, that show that shorter pulses do equivalent eye-damage for less energy only to certain limits, so why are you stating this exactly?

Next problem, the statement is actually wrong. Not just inaccurate, missleading or true only under certain conditions, actually self-contradictory. Irrispective of how much shorter the pulses are, if they are higher in energy you require more electrical energy in. Its a rule of thumb that I like to refer to as the conservation of mass/energy law.

"Now for a portable weapon, you will not be able to run a 5W weapon for long off a battery, and a pair of AA batteries would last for a few seconds CW."

By 5W weapon, I assume you mean a 5W laser beam rather than a weapon consuming 5W. Laser diodes can deliver about half of the power as emitted light so 10W. Lets assume rechargeable batteries, NiMH nowerdays can do 1900 to 2500mah claimed - lets assume 2000mah, 2.4v total or 4.8 Watt.Hours leading to a running time of a little under half an hour. Now I suppose half an hour is a certain number of seconds but a 'few'?

"So, what we do is we turn the laser on at those powers for very short times, in the order of tenths or less of a second. "

Ok, now its tenths of a second, in your last post you were doing maths to the tune of 1 microsecond. Could 5 orders of magnetude change in heart be anything to do with the 10% duty cycle quoted on the page later? I think it might.

"The shorter the pulse, to an extent, the more energy you can pour into it without burning out the laser diode, and the longer the batteries will last."

No to both.

"This is called the Duty Cycle."

No, Duty cycle is very simply the percentage of time the diodes are turned on. Clearly though this is where the 0.1 second comes from in your new estimate. You take 1 second by default, take the 10% duty cycle and end up with 0.1 second. To all intents and purposes its wrong, in that rated power, 10% duty cycle for 0.1 second on will burn out the diodes you are taking the data from. Reasonable numbers would be based on 100Hz pulses resulting in 1 ms pulse length for the same 10% duty cycle and without the embarrasment of killing some very expensive kit.

"Yes, you could wrongly remove the word "peak"."

1mj is the pulse energy, it is independant of time, the word 'peak' cannot be applied to it.

"punctuated by pulses of far higher power"

Yes, peak power, which is not relavent anyway, not 'peak energy' which is dimensionally incorrect.

"If you want to know if pulse compression works, go read about industry cutting diodes. "

Fibre coupled diodes are used to a very very limited extent for welding and cutting, they are not pulsed to the point they blast holes in the metal, this is simply not possible. Mostly I think you are digging up some info on high power diode arrays and assuming they do the actual cutting. The diode arrays do not cut and cannot be 'pulse compressed' to the extent they will abilate metal. All they are is a replacement for a flashlamp in the actual cutting laser itself, for example Nd:YAG.

"They run at higher powers, using arrays, heavy cooling and pulses! "

The pulses are not the limiting factor in the damage caused to the target, the rod they are powering is.

"They are pulsed very fast, at quite a high duty cycle"

Typically 100Hz, 10% Duty cycle. That the Duty cycle is high is because they cannot tolerate significantly higher power for even a much shorter period of time. This fundamentally undermines your argument, its a single order of magnetude 'compression' at the very most. In terms of actual peak pulse/CW power this is probably an overestimation due to the specific application. In other words with cooling designed for CW operation the bars could probably be run with significantly higher average power.

There follows a paragraph on why higher power does more damage in the field of cutting equipment. Again you make claims with no evidence, data or applicable limits to something that seems obvious. Regardless of truth, it is not relavent and not worth expounding on or correcting.

"throwing out 30kW in 10% of the time (yes, I know the units are wrong at this stage - it is a 30kJ pulse) causes far more energy absorption at the target, "

Energy = Power * Time. You cannot determine a pulse energy from a peak power and a duty cycle.

"every one of the arrays on there are 10% duty cycle pulsed diode arrays. "

No, they arnt. Some are even CW. They are all arrays designed for diode pumped applications, some must contain thousands of actual lasers.

"All the highest power diodes are pulsed"

Again, obvious and irrelavent. The highest power of anything is pulsed but peak power is not what does the work, energy is.

"You are seriously telling me that you think that exceeding is the only target? "

When all you have is a threshold its meaningless to discuss by how much something exceeds it. We have no frame of reference for interpreting the numbers, aside from being the standard for safety we dont even know what the threshold actually refers to, its only useful to compare them with eachother. 250x the threshold is meaningless, 2500x the threshold is bigger but equally meaningless. What is the point in even doing the maths if you have no way of understanding what the answer means?

"So you get hit by a megajoule pulse, and you think it would do the same eye damage as a 10mW CW laser because it is a few nanoseconds?"

Mindreader! Yes Jack, clearly thats exactly what I was stating, including that the former example has no time period or wavelength the latter has no energy or time period or wavelength and the phrase 'it is a few nanoseconds' applies only to time periods, how clever of you to decode it and how helpful for other people reading the thread.

"Because 1W == 1J/s, of course."

I see, you choose 1 second because 1 watt is 1 joule over 1 second. But then 1 watt is also 2 joules over 2 seconds, or 0.1J over 0.1 sec. Why not use Pi seconds on the basis 1W is Pi Joules over Pi seconds? Mmmm Pie.

"Because a Q-switch or other pulse compressor to do that has yet to be invented."

This is my point, a Q switch or other pulse compressor that will do 1 second has yet to be invented also.

". I am stating a well known fact. A short high power pulse does more damage than the same energy spread out. "

Yes, you are stating it again and again and again. We have allready established limits for when it is and is not true in this application. Now if your later argument is true, that you are pulsing 10x the rate for the same power, then your energy per pulse drops by a factor of 10, and thus the pulse power for any given length of pulse also drops by a factor of 10. This is not increasing peak power to do more damage as you claim. You have your wires crossed somewhere.

"You take the nominal maximum CW power for the diode, say 50mW, and you turn it into a set of compressed pulses"

How many pulses, over what period of time? It affects the answer and you don't state this.

"The higher energy per unit time, which gives us an indication of the damage to target from the figures you gave for eye-safe beams,"

No, energy per unit time does not. Energy and duration seperatly do.

"shows that this is a more effective way to damage the eye"

This does not follow, it might be true.

"the diode gets less efficient at higher pulse powers and shorter pulse times."

This is not a primary problem, diode lasers are very limited in terms of peak power.

"You need to select your diode for this application. However, you might be using a dye saturation Q switch, or a mode-locked laser, or a chirped pulse compression fibre, or whatever, running off a CW laser of almost any type."

You cannot Q switch a diode laser, dye saturation or otherwise. You cannot modelock a diode laser, you cannot use chirped pulse compression. You are using these terms without understanding to what they apply.

"However, compressing the pulse from CW down to higher (peak pulse) powers works. Industry do it all the time. "

Noone takes the output of a CW laser and compresses it into pulses. Noone.

"There is a hell of a lot of research into it, too. http://physics.unr.edu/grad/aguilar...cs709fall01.pdf is a fairly good paper on it."

This is not a good paper for this application, aside from anything else it reads like an undergraduate project. It probably is an undergraduate project. It explains some very basic concepts in increasing pulse power. Nowhere - *NOWHERE* - does it talk about pulse energy and all the methods explained cripple pulse energy in the pursuit of high peak power. This is useless for making cutting tools or weapons.

[Marvin]

"Ok, I never said that compressing the pulse from a standard laser diode was going to be trivial. "

I agree, in fact you havn't provided any evidence it can be done at all. Its a little like working out the maths for killing people by making all the hydrogen atoms in their body fuse to helium. Even if you get the maths right, you are still no closer to actually doing it.

"It is a fact that you can get sharp, high power pulses from diode lasers. "

How sharp, 1 second? 1 nanosecond? What diode lasers? How high a power? This is a meaningless statement without numbers let alone an actual 'fact'. In addition 'high power' is not a useful term as Ive allready shown, with or without numbers.

"It is also a fact that the shorter, higher energy pulses damage the eye whilst requiring a lot less electrical energy in."

Another 'fact', how much shorter? How much higher? How much damage? How much less energy in?
But wait, Ive already provided examples of that information, that show that shorter pulses do equivalent eye-damage for less energy only to certain limits, so why are you stating this exactly?

Next problem, the statement is actually wrong. Not just inaccurate, missleading or true only under certain conditions, actually self-contradictory. Irrispective of how much shorter the pulses are, if they are higher in energy you require more electrical energy in. Its a rule of thumb that I like to refer to as the conservation of mass/energy law.

"Now for a portable weapon, you will not be able to run a 5W weapon for long off a battery, and a pair of AA batteries would last for a few seconds CW."

By 5W weapon, I assume you mean a 5W laser beam rather than a weapon consuming 5W. Laser diodes can deliver about half of the power as emitted light so 10W. Lets assume rechargeable batteries, NiMH nowerdays can do 1900 to 2500mah claimed - lets assume 2000mah, 2.4v total or 4.8 Watt.Hours leading to a running time of a little under half an hour. Now I suppose half an hour is a certain number of seconds but a 'few'?

"So, what we do is we turn the laser on at those powers for very short times, in the order of tenths or less of a second. "

Ok, now its tenths of a second, in your last post you were doing maths to the tune of 1 microsecond. Could 5 orders of magnetude change in heart be anything to do with the 10% duty cycle quoted on the page later? I think it might.

"The shorter the pulse, to an extent, the more energy you can pour into it without burning out the laser diode, and the longer the batteries will last."

No to both.

"This is called the Duty Cycle."

No, Duty cycle is very simply the percentage of time the diodes are turned on. Clearly though this is where the 0.1 second comes from in your new estimate. You take 1 second by default, take the 10% duty cycle and end up with 0.1 second. To all intents and purposes its wrong, in that rated power, 10% duty cycle for 0.1 second on will burn out the diodes you are taking the data from. Reasonable numbers would be based on 100Hz pulses resulting in 1 ms pulse length for the same 10% duty cycle and without the embarrasment of killing some very expensive kit.

"Yes, you could wrongly remove the word "peak"."

1mj is the pulse energy, it is independant of time, the word 'peak' cannot be applied to it.

"punctuated by pulses of far higher power"

Yes, peak power, which is not relavent anyway, not 'peak energy' which is dimensionally incorrect.

"If you want to know if pulse compression works, go read about industry cutting diodes. "

Fibre coupled diodes are used to a very very limited extent for welding and cutting, they are not pulsed to the point they blast holes in the metal, this is simply not possible. Mostly I think you are digging up some info on high power diode arrays and assuming they do the actual cutting. The diode arrays do not cut and cannot be 'pulse compressed' to the extent they will abilate metal. All they are is a replacement for a flashlamp in the actual cutting laser itself, for example Nd:YAG.

"They run at higher powers, using arrays, heavy cooling and pulses! "

The pulses are not the limiting factor in the damage caused to the target, the rod they are powering is.

"They are pulsed very fast, at quite a high duty cycle"

Typically 100Hz, 10% Duty cycle. That the Duty cycle is high is because they cannot tolerate significantly higher power for even a much shorter period of time. This fundamentally undermines your argument, its a single order of magnetude 'compression' at the very most. In terms of actual peak pulse/CW power this is probably an overestimation due to the specific application. In other words with cooling designed for CW operation the bars could probably be run with significantly higher average power.

There follows a paragraph on why higher power does more damage in the field of cutting equipment. Again you make claims with no evidence, data or applicable limits to something that seems obvious. Regardless of truth, it is not relavent and not worth expounding on or correcting.

"throwing out 30kW in 10% of the time (yes, I know the units are wrong at this stage - it is a 30kJ pulse) causes far more energy absorption at the target, "

Energy = Power * Time. You cannot determine a pulse energy from a peak power and a duty cycle.

"every one of the arrays on there are 10% duty cycle pulsed diode arrays. "

No, they arnt. Some are even CW. They are all arrays designed for diode pumped applications, some must contain thousands of actual lasers.

"All the highest power diodes are pulsed"

Again, obvious and irrelavent. The highest power of anything is pulsed but peak power is not what does the work, energy is.

"You are seriously telling me that you think that exceeding is the only target? "

When all you have is a threshold its meaningless to discuss by how much something exceeds it. We have no frame of reference for interpreting the numbers, aside from being the standard for safety we dont even know what the threshold actually refers to, its only useful to compare them with eachother. 250x the threshold is meaningless, 2500x the threshold is bigger but equally meaningless. What is the point in even doing the maths if you have no way of understanding what the answer means?

"So you get hit by a megajoule pulse, and you think it would do the same eye damage as a 10mW CW laser because it is a few nanoseconds?"

Mindreader! Yes Jack, clearly thats exactly what I was stating, including that the former example has no time period or wavelength the latter has no energy or time period or wavelength and the phrase 'it is a few nanoseconds' applies only to time periods, how clever of you to decode it and how helpful for other people reading the thread.

"Because 1W == 1J/s, of course."

I see, you choose 1 second because 1 watt is 1 joule over 1 second. But then 1 watt is also 2 joules over 2 seconds, or 0.1J over 0.1 sec. Why not use Pi seconds on the basis 1W is Pi Joules over Pi seconds? Mmmm Pie.

"Because a Q-switch or other pulse compressor to do that has yet to be invented."

This is my point, a Q switch or other pulse compressor that will do 1 second has yet to be invented also.

". I am stating a well known fact. A short high power pulse does more damage than the same energy spread out. "

Yes, you are stating it again and again and again. We have allready established limits for when it is and is not true in this application. Now if your later argument is true, that you are pulsing 10x the rate for the same power, then your energy per pulse drops by a factor of 10, and thus the pulse power for any given length of pulse also drops by a factor of 10. This is not increasing peak power to do more damage as you claim. You have your wires crossed somewhere.

"You take the nominal maximum CW power for the diode, say 50mW, and you turn it into a set of compressed pulses"

How many pulses, over what period of time? It affects the answer and you don't state this.

"The higher energy per unit time, which gives us an indication of the damage to target from the figures you gave for eye-safe beams,"

No, energy per unit time does not. Energy and duration seperatly do.

"shows that this is a more effective way to damage the eye"

This does not follow, it might be true.

"the diode gets less efficient at higher pulse powers and shorter pulse times."

This is not a primary problem, diode lasers are very limited in terms of peak power.

"You need to select your diode for this application. However, you might be using a dye saturation Q switch, or a mode-locked laser, or a chirped pulse compression fibre, or whatever, running off a CW laser of almost any type."

You cannot Q switch a diode laser, dye saturation or otherwise. You cannot modelock a diode laser, you cannot use chirped pulse compression. You are using these terms without understanding to what they apply.

"However, compressing the pulse from CW down to higher (peak pulse) powers works. Industry do it all the time. "

Noone takes the output of a CW laser and compresses it into pulses. Noone.

"There is a hell of a lot of research into it, too. http://physics.unr.edu/grad/aguilar...cs709fall01.pdf is a fairly good paper on it."

This is not a good paper for this application, aside from anything else it reads like an undergraduate project. It probably is an undergraduate project. It explains some very basic concepts in increasing pulse power. Nowhere - *NOWHERE* - does it talk about pulse energy and all the methods explained cripple pulse energy in the pursuit of high peak power. This is useless for making cutting tools or weapons.

[Jacks Complete]

By 5W weapon, I assume you mean a 5W laser beam rather than a weapon consuming 5W. Laser diodes can deliver about half of the power as emitted light so 10W. Lets assume rechargeable batteries, NiMH nowerdays can do 1900 to 2500mah claimed - lets assume 2000mah, 2.4v total or 4.8 Watt.Hours leading to a running time of a little under half an hour. Now I suppose half an hour is a certain number of seconds but a 'few'?Given that my 50mW diode laser (DPSS) lasts for half an hour on to TRIPLE A batteries... but anyway. Yes, you are correct on that point. You could run in CW for maybe half an hour."The shorter the pulse, to an extent, the more energy you can pour into it without burning out the laser diode, and the longer the batteries will last."No to both.So your circuits use as much power when off as when on? The reason you can put higher electrical power into the diode is because it is quite a short time. Too long, and you will have too much electrical power turning into heat. This kills your diode very rapidly. The size of the junctions are generally micrometers, so you have to let them cool a little between shots, so they don't fry, and the heat has a little time to conduct away.

This is, in fact, a perfect analogy to why a short laser pulse does damage at a higher level than a longer pulse of the same total energy.

"So you get hit by a megajoule pulse, and you think it would do the same eye damage as a 10mW CW laser because it is a few nanoseconds?"

Mindreader! Yes Jack, clearly thats exactly what I was stating, including that the former example has no time period or wavelength the latter has no energy or time period or wavelength and the phrase 'it is a few nanoseconds' applies only to time periods, how clever of you to decode it and how helpful for other people reading the thread.You are obviously not well read on this stuff, or you are being obstructive.

If you think that shining a laser beam onto your foot, of a safe level, for a day, is ever, ever going to have the same effect as if you compress that pulse, you are plainly, obviously wrong. I wasn't trying to write an entire paper for a group of graduates.

Higher energy pulses give higher damage to targets. Heat that conducts away from the target before the end of the exposure is wasted energy.

Material processing uses high power pulses to avoid a heat affected zone. This is true at marginal powers, where otherwise a lot of energy would be used to heat around the target before the melting point was reached, due to conduction.

Therefore, the pulse is short and high powered. This melts the target almost instantly, and heat phonons do not have time to travel during the pulse. The initial melting also helps with absorption at IR wavelengths, especially in metals. The rest of the pulse is then absorbed, and the boiling point is reached, causing the material to enter the gaseous phase, and this increases the pressure dramatically. The plume of boiling metal explodes out of the hole. The next pulse comes down just next to it, and repeats the effect. Energy is also not wasted by pumping more energy into the plume of waste metal vapour.

With a CW laser of enough power, you could do this with CW. However, it would be far less efficient, would require higher power cooling, more batteries, etc. and would leave a bigger HAZ.

"You need to select your diode for this application. However, you might be using a dye saturation Q switch, or a mode-locked laser, or a chirped pulse compression fibre, or whatever, running off a CW laser of almost any type."

You cannot Q switch a diode laser, dye saturation or otherwise. You cannot modelock a diode laser, you cannot use chirped pulse compression. You are using these terms without understanding to what they apply.You are clearly being akward here. What part of "running off a CW laser of almost any type." did you miss?

As I said, I'm not writing a paper to present to an undergraduate class, full of caveats. I am writing to inform the members here that they can do this fairly easily, and get good results if they perform a fairly simple modification. That paper was one I found that could introduce you to the ideas behind pulse compression, something you seem to understand a little about. It is a graduate paper, and it appears to my eye to be correct.

Your statement "Noone takes the output from CW and compresses it into pulses. Noone." shows me that you didn't even read the first slide of the paper I linked. No-one, anywhere, has a CW laser capable, for example, of the magnetic field strengths attainable by a femto-second pulsed laser. HOWEVER, I am not saying that we should try to get these out of diode lasers, before you jump to that conclusion!

I am saying that, for the eye damage threshold figures you gave, a pulse compression down to the tens or hundreds of microseconds will give better eye damage results than the CW beam alone, if we increase the current through the diode at those times. It will also let the batteries last for far longer.

It is a well known fact that most diodes can be modulated into the MHz range, and even the worst ones can easily get to kHz. A higher energy 10 microsecond pulse is viable, will do more damage, and, if repeated every 1/10th of a second, will extend the battery life by about 10 times.

Yes, I have ommitted to take account of things like capacitor losses, reduced efficiency of the diode, etc. but this is not a symposium of laser physicists! No-one cares about the minutae here, they mostly care about how to make a better laser weapon.

To anyone undecided - when using a microwave oven, you get hot spots. This is because the energy tends to focus on one area. This will boil or burn food in one area, whilst the next area remains cold, as food tend to be fairly non-conductive.

If we reduce the power in, and spread it out over time, we find the food gets warm all the way through, as the heat has more time to conduct through the food.

Now imagine if we "saved up" the time when the microwave was off, and put it all into the food in one short pulse. You would boil the food, whilst the food around it would remain icy cold.

Short pulses boil rapidly, long ones boil slowly, CW warms (if we have the same average power in over time.) Which is better for attacking something that behaves like food?

[Jacks Complete]

By 5W weapon, I assume you mean a 5W laser beam rather than a weapon consuming 5W. Laser diodes can deliver about half of the power as emitted light so 10W. Lets assume rechargeable batteries, NiMH nowerdays can do 1900 to 2500mah claimed - lets assume 2000mah, 2.4v total or 4.8 Watt.Hours leading to a running time of a little under half an hour. Now I suppose half an hour is a certain number of seconds but a 'few'?Given that my 50mW diode laser (DPSS) lasts for half an hour on to TRIPLE A batteries... but anyway. Yes, you are correct on that point. You could run in CW for maybe half an hour."The shorter the pulse, to an extent, the more energy you can pour into it without burning out the laser diode, and the longer the batteries will last."No to both.So your circuits use as much power when off as when on? The reason you can put higher electrical power into the diode is because it is quite a short time. Too long, and you will have too much electrical power turning into heat. This kills your diode very rapidly. The size of the junctions are generally micrometers, so you have to let them cool a little between shots, so they don't fry, and the heat has a little time to conduct away.

This is, in fact, a perfect analogy to why a short laser pulse does damage at a higher level than a longer pulse of the same total energy.

"So you get hit by a megajoule pulse, and you think it would do the same eye damage as a 10mW CW laser because it is a few nanoseconds?"

Mindreader! Yes Jack, clearly thats exactly what I was stating, including that the former example has no time period or wavelength the latter has no energy or time period or wavelength and the phrase 'it is a few nanoseconds' applies only to time periods, how clever of you to decode it and how helpful for other people reading the thread.You are obviously not well read on this stuff, or you are being obstructive.

If you think that shining a laser beam onto your foot, of a safe level, for a day, is ever, ever going to have the same effect as if you compress that pulse, you are plainly, obviously wrong. I wasn't trying to write an entire paper for a group of graduates.

Higher energy pulses give higher damage to targets. Heat that conducts away from the target before the end of the exposure is wasted energy.

Material processing uses high power pulses to avoid a heat affected zone. This is true at marginal powers, where otherwise a lot of energy would be used to heat around the target before the melting point was reached, due to conduction.

Therefore, the pulse is short and high powered. This melts the target almost instantly, and heat phonons do not have time to travel during the pulse. The initial melting also helps with absorption at IR wavelengths, especially in metals. The rest of the pulse is then absorbed, and the boiling point is reached, causing the material to enter the gaseous phase, and this increases the pressure dramatically. The plume of boiling metal explodes out of the hole. The next pulse comes down just next to it, and repeats the effect. Energy is also not wasted by pumping more energy into the plume of waste metal vapour.

With a CW laser of enough power, you could do this with CW. However, it would be far less efficient, would require higher power cooling, more batteries, etc. and would leave a bigger HAZ.

"You need to select your diode for this application. However, you might be using a dye saturation Q switch, or a mode-locked laser, or a chirped pulse compression fibre, or whatever, running off a CW laser of almost any type."

You cannot Q switch a diode laser, dye saturation or otherwise. You cannot modelock a diode laser, you cannot use chirped pulse compression. You are using these terms without understanding to what they apply.You are clearly being akward here. What part of "running off a CW laser of almost any type." did you miss?

As I said, I'm not writing a paper to present to an undergraduate class, full of caveats. I am writing to inform the members here that they can do this fairly easily, and get good results if they perform a fairly simple modification. That paper was one I found that could introduce you to the ideas behind pulse compression, something you seem to understand a little about. It is a graduate paper, and it appears to my eye to be correct.

Your statement "Noone takes the output from CW and compresses it into pulses. Noone." shows me that you didn't even read the first slide of the paper I linked. No-one, anywhere, has a CW laser capable, for example, of the magnetic field strengths attainable by a femto-second pulsed laser. HOWEVER, I am not saying that we should try to get these out of diode lasers, before you jump to that conclusion!

I am saying that, for the eye damage threshold figures you gave, a pulse compression down to the tens or hundreds of microseconds will give better eye damage results than the CW beam alone, if we increase the current through the diode at those times. It will also let the batteries last for far longer.

It is a well known fact that most diodes can be modulated into the MHz range, and even the worst ones can easily get to kHz. A higher energy 10 microsecond pulse is viable, will do more damage, and, if repeated every 1/10th of a second, will extend the battery life by about 10 times.

Yes, I have ommitted to take account of things like capacitor losses, reduced efficiency of the diode, etc. but this is not a symposium of laser physicists! No-one cares about the minutae here, they mostly care about how to make a better laser weapon.

To anyone undecided - when using a microwave oven, you get hot spots. This is because the energy tends to focus on one area. This will boil or burn food in one area, whilst the next area remains cold, as food tend to be fairly non-conductive.

If we reduce the power in, and spread it out over time, we find the food gets warm all the way through, as the heat has more time to conduct through the food.

Now imagine if we "saved up" the time when the microwave was off, and put it all into the food in one short pulse. You would boil the food, whilst the food around it would remain icy cold.

Short pulses boil rapidly, long ones boil slowly, CW warms (if we have the same average power in over time.) Which is better for attacking something that behaves like food?

[Marvin]

J>Given that my 50mW diode laser (DPSS) lasts for half an hour on to TRIPLE A batteries...

If it is a 50mw diode laser then there is something seriously wrong with the design.


J>The shorter the pulse, to an extent, the more energy you can pour into it without burning out the laser diode, and the longer the batteries will last.

M>No to both.

J>So your circuits use as much power when off as when on?

You used the term 'energy' not power and that makes both statements wrong.

J>The reason you can put higher electrical power into the diode is because it is quite a short time. Too long, and you will have too much electrical power turning into heat. This kills your diode very rapidly. The size of the junctions are generally micrometers, so you have to let them cool a little between shots, so they don't fry, and the heat has a little time to conduct away.

You are providing no information. Replace the word 'diode' with 'motor' and 'junction' with 'coil' and nothing else changes, its just as intrinsically right or wrong as it was before.

J>This is, in fact, a perfect analogy to why a short laser pulse does damage at a higher level than a longer pulse of the same total energy.

I agree, but furthur its an excellent analogy as to why shortening the pulse of laser diodes cannot be used in this way for cutting metal. If the diode CW cannot be used to melt the metal then you have a degree of parity between the lasing material and the volume of metal to be cut. Anything you can do to increase the damage to the target will also affect the active volume of the laser in the same way. The only way out of it is to increase the volume of the laser (bigger or more of them, or to compress the energy after it has left (typically making them pumps in another laser alltogether)).

J>You are obviously not well read on this stuff, or you are being obstructive.

Can you not tell the difference? Your question was farcical even ignoring the clear implications of the data I posted, I responded in kind.

Pointless underlining of things I have allready agreed with skipped. What matters is how relavent your example is to your argument.

J>You are clearly being akward here. What part of "running off a CW laser of almost any type." did you miss?

Probably the part where you admit 'almost any type' fails to apply to the majority of laser types or the specific example you chose for the discussion.

J>I am writing to inform the members here that they can do this fairly easily, and get good results if they perform a fairly simple modification.

The crux of the matter, and I am pointing out why this will not work. Were these purposes somehow unclear in previous posts?

J>That paper was one I found that could introduce you to the ideas behind pulse compression, something you seem to understand a little about.

Yes, and none of the ideas in the paper are simple modifications, and none will work on your example, the diode laser. Thus the paper does not aid people in trying to do what you have suggested, and nor does it support your methods.

J>Your statement "Noone takes the output from CW and compresses it into pulses. Noone." shows me that you didn't even read the first slide of the paper

There are no examples of CW lasers mentioned in the paper. I'm not suggesting noone uses pulsed lasers, this is totally different.

J>I am saying that, for the eye damage threshold figures you gave, a pulse compression down to the tens or hundreds of microseconds will give better eye damage results than the CW beam alone,

'Down to' implies a 'from', without which its feasability cannot be determined.

J>if we increase the current through the diode at those times. It will also let the batteries last for far longer

This does not follow as written, but I know what you are trying to say. Choose either damage or battery power criteria, you cant play both cards, only one or the other can be optimised fully.

J>It is a well known fact that most diodes can be modulated into the MHz range

Modulated does not equate to being overdriven. Modulation is dependant mainly on the stimulated emission lifetime, which is in the sub nanosecond range for a laser diode. GHz modulation is feasable.

J>A higher energy 10 microsecond pulse is viable, will do more damage,

Another meaningless statement, does 'higher' mean 1% more or 100x more? Higher than what? More damage than what? How much more? What are you actually compairing the 10 microsecond pulse *to*?

J>Yes, I have ommitted to take account of things like capacitor losses, reduced efficiency of the diode

Trivial things, what have you taken into account though? Anything? Do results based on guessed numbers have any more meaning than guessed numbers themselves?

J>To anyone undecided

Real world physics does not depend on majority opinion. Is this why you make statements with no content? Attempt to show something works according to physics or don't bother arguing.

J>when using a microwave oven, you get hot spots. This is because the energy tends to focus on one area. This will boil or burn food in one area, whilst the next area remains cold, as food tend to be fairly non-conductive.
J>If we reduce the power in, and spread it out over time, we find the food gets warm all the way through, as the heat has more time to conduct through the food.
J>Now imagine if we "saved up" the time when the microwave was off, and put it all into the food in one short pulse. You would boil the food, whilst the food around it would remain icy cold.

You are still hung up on this storing up the energy and releasing it in one go for more damage. Look 5 or 6 posts previously and we have actual data for this. Whats more you leave it open to assumption that the shorter the pulse the more damage with no limits. You completely ignore the only parts of the problem actually open to interpretation, fortunatly, this can be added.

Lets assume some actual numbers for our example and pick out trends that result. Lets assume heat in our pizza travels at 1cm/second and our spot size is 1cm. Lets also assume a thin pizza, and that the depth is heated all the way through, I'll take Pi to be equal to 3 to make the maths easier. Ok, if we heat the middle for 10 seconds its clear that the whole of a 20cm pizza would be heated. Not that evenly but some energy would go everywhere, for an equivlent flat hot area of 150ish cm^2. This comes from the area of a circle Pi*r^2 for a 10cm radius pizza assuming that the heated area ranging from 0 to x degrees is equivalent in energy loss terms to half that area at a flat x degrees. This gives us our energy in the hotspot as being around 0.5% of the total spread out for 0.5% of the temperature, and thus effect, we could in theory get.

Now, how about for 1 second? We get a 2cm circle of heated area ramping up to the 1cm hotspot for an equivalent flat area of about 3 cm^2 + the 0.75 cm^2 hot spot (which we can assume to be thermally flat itself). We now have around 20% of the energy in the hotspot area, so 40x the energy density for a pulse 1/10th as long. Thats a big effect, does it continue?

How about for 0.1 second? We get a 1mm leak around the hotspot and the math now gives us 82% of the energy in the hotspot compaired to the total. An order of magnetude change in pulse length and now only a factor of just over 4 change in effect.

For 0.01 second? 98%.

Is it really worth going any furthur? Theres only 2% total improvement to get. Below a 0.1sec pulse length in this example the result is determined far more by a factor of 2 pulse energy than orders of magnetude change in pulse length.

Requirements. For a useful effect the pulse energy must be enough to boil the hot spot pizza area. Below that energy no change in pulse length however extreme will see anything happen. Pulse energy determines the limit of what can happen for a given active volume, pulse length determines what percentage of that energy stays at the target.

For us to reduce the pulse length to 1/10th and keep the same pulse energy we have to know that the magnetron will handle an increase in power by an order of magnetude. It has to operate normally at 10x power output without blowing up or breaking down for the whole duration of the pulse. For a step where the power throughput is less than parity, same energy, shorter time period, we need to know alowed power levels to determine if the saving on leaked energy exceeds the reduced pulse energy for a bigger effect.

Moving this over to the laser problem we don't need to do the same math, as we are given the time constant fairly clearly from the ANSI data, of 0.1ms. Lets take this data and actually ask the question, for a laser diode in the region of 50mw can we boost the power to the point we can pack significantly more energy into a 0.1ms period than would be present running CW?

Sanyo laser diodes,
DL-LS1068, 662nm (Red), 50mw. Maximum it can be driven to is 90mw at 50% Duty cycle, less than twice. Maximum length of time this can be sustained for is 100ns. ns!

DL-7140-201S, 785nm (NIR), Listed as a 70mw laser its actual rated peak CW is 80mw. Peak pulse is 85mw. Maximum length of peak pulse is 1us. Less than 10% increase in power but 2 orders of magnetude short of the goal pulse length.

DL-7240-201P, 782nm (NIR), 90mw CW, peak pulse 200mw, maximum length of peak pulse is 100ns, unsurprising given the other results.

Typical maximum data from real laser diodes and you know what? I feel a conclusion coming on. The peak powers arnt several orders of magntude higher, as in your original maths, they arnt even 1 order of magnetude higher in your last lot, they are between 1 and just over 2 and the maximum pulse length for a doubling in power is around 100ns. 3 orders of magnetude below what is needed giving us a 0.1ms pulse thats actually barely more power than the CW ratings. Bluntly the idea fails for 2 main reasons, firstly the diodes cannot support much more than CW rated power and secondly the time constant for damage is 3 orders of magnetude shorter than the time constant for damaging the target so if it fails to exceed thresholds for CW pulsing will not help.

Moving to the wider scope of 'pulse compression' ideas, would this method work on any other laser? There are only a few lasers that produce pulses longer than 0.1ms, giant pulse crystal lasers spring to mind but they are operating so slowly for good reason, they are exceeding the energy limits in the rod and the pulses cannot be shortened. CW lasers? Aside from diodes we only really have gas lasers and CW pumped crystals, the former cant be overdriven worth a damn and the latter is limited by extremely low doping in the rod. Chemical lasers are out, dye lasers are out.

Conclusion, can this idea for improving the damage of a weapon actually be made to work? No, not for diode lasers, not for any type of laser I can think of. Its simply a matter of running things at the rated powers and getting what you pay for.

[Marvin]

J>Given that my 50mW diode laser (DPSS) lasts for half an hour on to TRIPLE A batteries...

If it is a 50mw diode laser then there is something seriously wrong with the design.


J>The shorter the pulse, to an extent, the more energy you can pour into it without burning out the laser diode, and the longer the batteries will last.

M>No to both.

J>So your circuits use as much power when off as when on?

You used the term 'energy' not power and that makes both statements wrong.

J>The reason you can put higher electrical power into the diode is because it is quite a short time. Too long, and you will have too much electrical power turning into heat. This kills your diode very rapidly. The size of the junctions are generally micrometers, so you have to let them cool a little between shots, so they don't fry, and the heat has a little time to conduct away.

You are providing no information. Replace the word 'diode' with 'motor' and 'junction' with 'coil' and nothing else changes, its just as intrinsically right or wrong as it was before.

J>This is, in fact, a perfect analogy to why a short laser pulse does damage at a higher level than a longer pulse of the same total energy.

I agree, but furthur its an excellent analogy as to why shortening the pulse of laser diodes cannot be used in this way for cutting metal. If the diode CW cannot be used to melt the metal then you have a degree of parity between the lasing material and the volume of metal to be cut. Anything you can do to increase the damage to the target will also affect the active volume of the laser in the same way. The only way out of it is to increase the volume of the laser (bigger or more of them, or to compress the energy after it has left (typically making them pumps in another laser alltogether)).

J>You are obviously not well read on this stuff, or you are being obstructive.

Can you not tell the difference? Your question was farcical even ignoring the clear implications of the data I posted, I responded in kind.

Pointless underlining of things I have allready agreed with skipped. What matters is how relavent your example is to your argument.

J>You are clearly being akward here. What part of "running off a CW laser of almost any type." did you miss?

Probably the part where you admit 'almost any type' fails to apply to the majority of laser types or the specific example you chose for the discussion.

J>I am writing to inform the members here that they can do this fairly easily, and get good results if they perform a fairly simple modification.

The crux of the matter, and I am pointing out why this will not work. Were these purposes somehow unclear in previous posts?

J>That paper was one I found that could introduce you to the ideas behind pulse compression, something you seem to understand a little about.

Yes, and none of the ideas in the paper are simple modifications, and none will work on your example, the diode laser. Thus the paper does not aid people in trying to do what you have suggested, and nor does it support your methods.

J>Your statement "Noone takes the output from CW and compresses it into pulses. Noone." shows me that you didn't even read the first slide of the paper

There are no examples of CW lasers mentioned in the paper. I'm not suggesting noone uses pulsed lasers, this is totally different.

J>I am saying that, for the eye damage threshold figures you gave, a pulse compression down to the tens or hundreds of microseconds will give better eye damage results than the CW beam alone,

'Down to' implies a 'from', without which its feasability cannot be determined.

J>if we increase the current through the diode at those times. It will also let the batteries last for far longer

This does not follow as written, but I know what you are trying to say. Choose either damage or battery power criteria, you cant play both cards, only one or the other can be optimised fully.

J>It is a well known fact that most diodes can be modulated into the MHz range

Modulated does not equate to being overdriven. Modulation is dependant mainly on the stimulated emission lifetime, which is in the sub nanosecond range for a laser diode. GHz modulation is feasable.

J>A higher energy 10 microsecond pulse is viable, will do more damage,

Another meaningless statement, does 'higher' mean 1% more or 100x more? Higher than what? More damage than what? How much more? What are you actually compairing the 10 microsecond pulse *to*?

J>Yes, I have ommitted to take account of things like capacitor losses, reduced efficiency of the diode

Trivial things, what have you taken into account though? Anything? Do results based on guessed numbers have any more meaning than guessed numbers themselves?

J>To anyone undecided

Real world physics does not depend on majority opinion. Is this why you make statements with no content? Attempt to show something works according to physics or don't bother arguing.

J>when using a microwave oven, you get hot spots. This is because the energy tends to focus on one area. This will boil or burn food in one area, whilst the next area remains cold, as food tend to be fairly non-conductive.
J>If we reduce the power in, and spread it out over time, we find the food gets warm all the way through, as the heat has more time to conduct through the food.
J>Now imagine if we "saved up" the time when the microwave was off, and put it all into the food in one short pulse. You would boil the food, whilst the food around it would remain icy cold.

You are still hung up on this storing up the energy and releasing it in one go for more damage. Look 5 or 6 posts previously and we have actual data for this. Whats more you leave it open to assumption that the shorter the pulse the more damage with no limits. You completely ignore the only parts of the problem actually open to interpretation, fortunatly, this can be added.

Lets assume some actual numbers for our example and pick out trends that result. Lets assume heat in our pizza travels at 1cm/second and our spot size is 1cm. Lets also assume a thin pizza, and that the depth is heated all the way through, I'll take Pi to be equal to 3 to make the maths easier. Ok, if we heat the middle for 10 seconds its clear that the whole of a 20cm pizza would be heated. Not that evenly but some energy would go everywhere, for an equivlent flat hot area of 150ish cm^2. This comes from the area of a circle Pi*r^2 for a 10cm radius pizza assuming that the heated area ranging from 0 to x degrees is equivalent in energy loss terms to half that area at a flat x degrees. This gives us our energy in the hotspot as being around 0.5% of the total spread out for 0.5% of the temperature, and thus effect, we could in theory get.

Now, how about for 1 second? We get a 2cm circle of heated area ramping up to the 1cm hotspot for an equivalent flat area of about 3 cm^2 + the 0.75 cm^2 hot spot (which we can assume to be thermally flat itself). We now have around 20% of the energy in the hotspot area, so 40x the energy density for a pulse 1/10th as long. Thats a big effect, does it continue?

How about for 0.1 second? We get a 1mm leak around the hotspot and the math now gives us 82% of the energy in the hotspot compaired to the total. An order of magnetude change in pulse length and now only a factor of just over 4 change in effect.

For 0.01 second? 98%.

Is it really worth going any furthur? Theres only 2% total improvement to get. Below a 0.1sec pulse length in this example the result is determined far more by a factor of 2 pulse energy than orders of magnetude change in pulse length.

Requirements. For a useful effect the pulse energy must be enough to boil the hot spot pizza area. Below that energy no change in pulse length however extreme will see anything happen. Pulse energy determines the limit of what can happen for a given active volume, pulse length determines what percentage of that energy stays at the target.

For us to reduce the pulse length to 1/10th and keep the same pulse energy we have to know that the magnetron will handle an increase in power by an order of magnetude. It has to operate normally at 10x power output without blowing up or breaking down for the whole duration of the pulse. For a step where the power throughput is less than parity, same energy, shorter time period, we need to know alowed power levels to determine if the saving on leaked energy exceeds the reduced pulse energy for a bigger effect.

Moving this over to the laser problem we don't need to do the same math, as we are given the time constant fairly clearly from the ANSI data, of 0.1ms. Lets take this data and actually ask the question, for a laser diode in the region of 50mw can we boost the power to the point we can pack significantly more energy into a 0.1ms period than would be present running CW?

Sanyo laser diodes,
DL-LS1068, 662nm (Red), 50mw. Maximum it can be driven to is 90mw at 50% Duty cycle, less than twice. Maximum length of time this can be sustained for is 100ns. ns!

DL-7140-201S, 785nm (NIR), Listed as a 70mw laser its actual rated peak CW is 80mw. Peak pulse is 85mw. Maximum length of peak pulse is 1us. Less than 10% increase in power but 2 orders of magnetude short of the goal pulse length.

DL-7240-201P, 782nm (NIR), 90mw CW, peak pulse 200mw, maximum length of peak pulse is 100ns, unsurprising given the other results.

Typical maximum data from real laser diodes and you know what? I feel a conclusion coming on. The peak powers arnt several orders of magntude higher, as in your original maths, they arnt even 1 order of magnetude higher in your last lot, they are between 1 and just over 2 and the maximum pulse length for a doubling in power is around 100ns. 3 orders of magnetude below what is needed giving us a 0.1ms pulse thats actually barely more power than the CW ratings. Bluntly the idea fails for 2 main reasons, firstly the diodes cannot support much more than CW rated power and secondly the time constant for damage is 3 orders of magnetude shorter than the time constant for damaging the target so if it fails to exceed thresholds for CW pulsing will not help.

Moving to the wider scope of 'pulse compression' ideas, would this method work on any other laser? There are only a few lasers that produce pulses longer than 0.1ms, giant pulse crystal lasers spring to mind but they are operating so slowly for good reason, they are exceeding the energy limits in the rod and the pulses cannot be shortened. CW lasers? Aside from diodes we only really have gas lasers and CW pumped crystals, the former cant be overdriven worth a damn and the latter is limited by extremely low doping in the rod. Chemical lasers are out, dye lasers are out.

Conclusion, can this idea for improving the damage of a weapon actually be made to work? No, not for diode lasers, not for any type of laser I can think of. Its simply a matter of running things at the rated powers and getting what you pay for.