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ArcticMyst Security by Avery

Flame Pumped Laser

Joined
Aug 14, 2013
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I had been thinking about CO2 lasers and the YAL-1 the other day when I was sitting in front of a bonfire and it occurred to me that there must be some stimulated emissions type of thing going on in the fire. So I thought why not put some ZnSe optics around a flame of some kind and use the energy already imparted to the molecules as a pump. Well, apparently I am not the first to come up with this idea.

Flame pumping and infrared maser action in CO2

So, apparently this has already been done and terrific output powers can be achieved. If there is anyone out there in EDU, I imagine this would be a good read as I can't afford to purchase the full article. :thinking: It is possible that much of the heat felt when standing next to a large fire is from 10.6um emission of the CO2 molecules. Would a standard diffraction grating even work at this frequency? If so, how would you even "see" an emission line at this low of a wavelength? Just a few thoughts in the hope that this gets someone else's brain out there working.:thanks:
 





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It is possible that much of the heat felt when standing next to a large fire is from 10.6um emission of the CO2 molecules

No. Almost all the light from a campfire is blackbody radiation.

Would a standard diffraction grating even work at this frequency?

No. You would have to make your own double-slit if you wanted to split mid-IR.

how would you even "see" an emission line at this low of a wavelength?

The same way you "see" the heat from the campfire. You can also buy very expensive equipment to analyse it.
 
Joined
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:thanks: I had almost completely forgotten about this. If it works, I can think of a couple advantages of a flame pumped laser and a few disadvantages. One advantage would be no bulky HV power supply. All of the power comes directly from combustion. Another would be operation at atmospheric pressure. No vacuum pumps. Some disadvantages might be difficulty controlling the effective output and flicker.

After doing some more reading, however I don't expect very much output from something like this. It appears that at higher temperatures CO2 stays mostly in 010, not the 100 energy level needed to lase. The gasses would have to be cooled very quickly after combustion before the states have a chance to decay. It's something to try though if I ever end up with the right optics. I'm sure some lasing would happen even at the higher temperatures, but it wouldn't be terribly efficient.
 

LSRFAQ

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There once upon a time was a flame pumped, very tiny, copper vapor. The developer said it took him about a year to get the gas doping, mirrors, and high speed flow right.

Not a easy one, he used acetylene with the bromide salts.

The flow has to be fast, the lasing medium needs to pass through the optical in a few nanoseconds.

I cant find the reference, and even then, details were sparse.

Steve
 
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AUS

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I was reading a patent on flame excited lasers a while ago. From memory you need a very stable high speed burning jet of gas through a special nozzle in a cavity with optics. I think the actual lasing medium was fed in with the fuel mixture (I think it was a fairly exotic gas mix).

This isn't too different from the huge military chemical lasers which are basically a big jet engine with optics at one end burning nasty stuff containing fluorine and chlorine.
 
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The common theme here seems to be a rocket-like discharge. The excited states don't last
very long, so the atoms have to get into the cavity quickly. Then they lase fast and have to
be replaced quickly with new ones.

I can see why that guy decided to go with copper vapor. It will lase at higher temperatures,
so there doesn't need to be special nozzles for cooling as in a CO2 chemical laser.
 




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