Question: Pulse Laser, Taser, Marx Generator?

[shintashi]

On the internet I see a handful of high powered short duration flashes of laser light in seemingly compact designs that others apparently call "pulsed". I've also seen tasers produce ludicrous amounts of voltage and effective stunning power in a hand held device that betrays my understanding of battery size vs. voltage. Finally I've seen a marx generator create high powered spark gaps using nothing more than a double A battery.

I'm wondering if these three technologies are some how interrelated, and ultimately would like to understand this processes of short bursts of high energy sufficient to experiment safely, particularly with a pulse laser at the end of this road.

I'm also curious about laser diodes and whether or not an intensely bright/hot beam can be emitted for a very short time without burning out the LD, and if there's such a thing as a chart or known figures or estimates as to how that (shorter duration:higher energy) diverges.

For example, if I take a blue 1W LD, can I reach something like 100W for a fraction of a second? If yes, how much more can be achieved without irrevocably destroying the diode? If the answer is no, then what is the maximum "flash" achievable?

If my hypothesis is incorrect, and I would need a completely different kind of diode, what kind of diode would I need to get short term high energy bursts?

 

[Arayan]

a pulsed laser simply means "intermittent" and can also be obtained with a diode laser, but that of which you speak is another thing
Such a short pulse are obtained from solid state laser typically operated in the so called Q-switching mode, an optical switch that is inserted in the laser cavity.

Sam's Laser FAQ - Commercial Solid State Lasers

 

[HIMNL9]

For laser diodes, same as for LEDs, the power is related to the time of emission, so, GENERICALLY speaking, you can obtain short pulses with higher powers ..... but also, laser diodes are more delicate than LEDs, so there are some more limits.

THEORICALLY speaking, your idea is correct, but in the reality the limits are very shorts (if you want that your devices survive )

As example, with LEDs, there is a "safe enough" factor (if you want to call it this way ) of 10, that means that you can feed the LED for 1/10 of second with 10 times the max current and still have it survive ..... on seconds basis, ofcourse ..... more clearly, if you have a LED with max current of 20mA, you can feed it safely with 200mA for 100mS, each second (100mS on / 900mS off) ..... you can do more, but probably they die in short time (i used some superbright red LEDs at 1,5A pulsed 20mS on / 1,5S off, and they survived long time, and tried one of these 10W DX LED in a flashing system that power it with 12A pulses for 100mS each 2 seconds too, still working, but is not a warranty that any other LEDS can do the same).

Laser diodes are more sensitive, especially for the heat factor, so you can probably feed one of them at higher currents, pulsed, but not so much as LEDs ..... probably, a safe level for, say, one of the 445nm 1W ones, can be like 3 times the maximum CW current for 100 or 150mS, not more than one pulse per second, with good heat dissipation.

Also, there is no way for give a sure reply, also cause LDs are different one from another, sometimes (as "freaky diodes" demonstrates) ..... you can also take 2 identical LDs, power them in identical ways, and have one living forever and the other going LEDed after 5 minutes, without apparent reasons.

 

[Sigurthr]

Current is the key in all those battery size vs. voltage examples you cited earlier. Both in tasers and marx generators (as well as CW multipliers, and simple transformers) as you increase the voltage you decrease the current.

You can get 1500V out of a 1.5V battery but the current will be 1/1000 of what you would normally get out of it.

 

[Seoul_lasers]

On the internet I see a handful of high powered short duration flashes of laser light in seemingly compact designs that others apparently call "pulsed". I've also seen tasers produce ludicrous amounts of voltage and effective stunning power in a hand held device that betrays my understanding of battery size vs. voltage. Finally I've seen a marx generator create high powered spark gaps using nothing more than a double A battery.

I'm wondering if these three technologies are some how interrelated, and ultimately would like to understand this processes of short bursts of high energy sufficient to experiment safely, particularly with a pulse laser at the end of this road.

I'm also curious about laser diodes and whether or not an intensely bright/hot beam can be emitted for a very short time without burning out the LD, and if there's such a thing as a chart or known figures or estimates as to how that (shorter duration:higher energy) diverges.

For example, if I take a blue 1W LD, can I reach something like 100W for a fraction of a second? If yes, how much more can be achieved without irrevocably destroying the diode? If the answer is no, then what is the maximum "flash" achievable?

If my hypothesis is incorrect, and I would need a completely different kind of diode, what kind of diode would I need to get short term high energy bursts?

IF we are talking air breakdown and lasers creating a conductive path for HV to flow then a diode laser will NOT work! Reason, you need 1000's of Watts ~(1MW) of output power to achieve this for a very short amount of time ~ around 20nS. Think ruby laser or a Nd:Yag. Experiments using Nd:yag lasers were successful in conducting (directing) a charge by a private defence firm a few years ago. So the verdict here is that NO diode laser has impulse power to the same level that a pulsed flash lamp based laser has. 100W/sec vs +1MW/20nS

Secondly about tasers. ALL commerical Tasers deliver a maximum of 60Kvdc. There is NO such a taser that delivers more than this. Thats means that at 60Kv you have a spark that jumps ~5-6cm.
IF you were going to direct this using a laser you'd need a lot more potential. 100's of KV or more!