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ArcticMyst Security by Avery

do it yourself portable gas lasers

Joined
Jan 2, 2008
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A newb once built a portable CO2 laser
When he started it up it acted just like a tazer.

It fried his brain and crisped his hand
It burnt his eyes just like a eggs in a pan

He wanted more power, which is what he got.
Too bad for him - He now, is not.
 
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If you want an ungodly amount of power and you want it portable CO2 is the WRONG way to go. Get a flashlamp along with a Nd:YAG rod and some mirrors
 
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If you want an ungodly amount of power and you want it portable CO2 is the WRONG way to go. Get a flashlamp along with a Nd:YAG rod and some mirrors

While that's nice for a pulsed setup (burst power 100's to 1000KW), 1 shot every 5-10 seconds, a CO2 laser puts out in Continuous Wave in 10's to 100's of watts for small to medium sized tubes. This = serious cutting power.

- The average power is actually fairly small for portable YAGs and is measured in 100's of mJ to 10-20J
This is the WRONG way to go if you're into cutting or surface cleaning.


Nowhere near a CO2's continuous output (smallest tube) 40J - +100J for medium tubes .

:gun:

Hope this explains why flash lamp pumped YAGs aren't really that good for doing cutting and
better for ranging/targeting on a Abrams tank.
 
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Joined
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you're forgetting that to cut with a co2 laser, you need a lens. typically, the fl of lenses used for co2 cutting are 20mm, 50mm, or 75mm.

completely impractical for anything non stationary.

also, no one has mentioned the UV hazard from the co2 plasma.

don't do it.

the are more interesting ways to damage yourself and the things around you.

While that's nice for a pulsed setup (burst power 100's to 1000KW), 1 shot every 5-10 seconds, a CO2 laser puts out in Continuous Wave in 10's to 100's of watts for small to medium sized tubes. This = serious cutting power.
 
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also, no one has mentioned the UV hazard from the co2 plasma.

The UV is blocked by the glass that encases it. There is no UV hazard unless you use an obscure material like quartz for the tube.

You don't get a tan from your computer screen or your office lights for the same reason.
 
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Curtains have a bad habit of collecting loose dust
on the fibers. This dust can ignite in a flash!
Stay away from them even when cleaned.
Getting more haha power haha isn't always funny.
HMike
 
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I have been setting up the tooling I need to build an efficient, non-portable CO2 laser for the application of sintering glass. A portable version is difficult to ignore!

A rule-of-thumb says that you get up to 80W per meter of 100 torr sealed CO2 optical cavity, but with Q-switching this can be turned into high-intensity pulses. When you Q-switch a CW laser the CO2 takes a charge just like a capacitor and then when the stimulated emission part of the laser process is switched back on, the capacitor discharges all the energy it stored up when the q-switch was off.


Gallium Arsenide is an optimal choice for CO2 optics. Making lenses out of it isn't impossible, but it does require more than a passing interest. With a metamaterial of GaAs/AlAs you can exploit the berirefringent and piezoelectric properties of these materials to Q-switch at extreme Pulse Repetition Rates. This pulsed mode lets you make a very effective cutting laser since there isn't always a cloud of plasma in front of your ablation target, and the electrical requirements for the same effect are perhaps halved.

Pulsing can be taken to an even further extreme with Chirped Pulse Amplification.

Historically there has been little real effort to make CO2 lasers more effective than about 20% input to output. The length of the optical cavity for example is almost always opaque to mid-IR, meaning it requires a lot of cooling for all the energy it wastes as heat. The quantum rules of lasing however say that the direction that an electron emits a photon is always random, implying that the entire optical cavity should have its reflectivity q-switched. My guesstimate is that if you do this then the 20-80 ratio is reversed.


you're forgetting that to cut with a co2 laser, you need a lens. typically, the fl of lenses used for co2 cutting are 20mm, 50mm, or 75mm.

If you swap out the glass in an auto-focusing camera objective and slave it to another identical objective with original glass, you have a crude hack to focus the beam at your desired distance. This also lets you overcome the air ionization problem and you can even ablate mid-IR reflective materials by zapping the air right in front of them.

Air ionization means that quite a lot of energy gets reflected back into the lens and on the return path it may damage the system. With auto-focus distance data and GaAs/AlAs you could probably Q-switch again to occlude returns from re-entering the system.
 
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Joined
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If you swap out the glass in an auto-focusing camera objective and slave it to another identical objective with original glass, you have a crude hack to focus the beam at your desired distance. This also lets you overcome the air ionization problem and you can even ablate mid-IR reflective materials by zapping the air right in front of them.

of course a longer focal length results in a larger minimal focal size which negatively impacts the energy density at the focal point.
 
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I didn't know that camera glass will
pass 10,600 IR. Coated BK-7 works
OK with Nd:Yag lasers.
HMike
 
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Jan 14, 2009
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I didn't know that camera glass will
pass 10,600 IR. Coated BK-7 works
OK with Nd:Yag lasers.
HMike

Normal Glass wont pass 10.6uM so camera lenses wont either , its has to be something alone the lines of ZnSe or Germanium based for it to work with 10.6uM light .
 
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