Budget CO2 lasers?

Rivem said:

I've been looking into a way to get into high power (>20W) lasers recently without much luck, so I figured I'd go ahead and finally make an account to ask you all.

I'm working on a home experiment that involves burning a small amount of material at a high temperature in a vacuum chamber. A laser would be most ideal for this, but I'd need a significant power level. This is also a fairly expensive project without the laser, so I'd like to keep costs at a minimum. Diode and flashlamp pumped lasers could probably do the job, but a CO2 laser was the first thing to come to mind.

Do you have any suggestions on minimizing the cost of high power lasers? I'm fine going for used or just parts. I know people have been able to get the necessary parts free from medical facilities, but I don't expect anybody in my area to have old enough systems to retire. Would it be cheaper to go another laser route?

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diachi said:

A cheap CO2 laser from China is probably your best bet if you want to go for CO2 - maybe see if you can find something used on eBay. Alternatively, you could try the buy/sell/trade section here or on Photonlexicon.com to see if anyone has anything.

Keep in mind, you'll need a window made of ZnSe or NaCl so that the light from the CO2 laser can pass into your vacuum chamber - borosilicate glass and most other glasses won't work at 10.6um. I don't know how well either of those materials would hold up under pressure - I imagine ZnSe would do fairly well, you should be able to look up the specs on ZnSe laser windows to find something that'd suit your needs. The other option, if your chamber is big enough, is to put the laser inside of the chamber. That may cause other issues though - CO2 lasers often require water cooling for one, so you'd need to run water into the chamber somehow, as well as power for the tube. https://www.lasercomponents.com/de-en/product/znse-windows-for-co2-lasers/

A high power fibre coupled laser diode at ~800nm might be a good option - regular borosilicate glass has ~90% transmission at that wavelength. Fibre coupling would allow you to get a relatively round and even beam too. CO2 would be good for the same reason i.e., a fairly round and even beam.

What's your budget?

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Rivem said:

Thanks for the input.

The plan is to use a ZnSe window if I go this route. It should almost definitely meet specs. The chamber will be small, so laser has to be outside in the gas route.

I've looked at the fiber-coupled lasers, and they seem like they may be a decent option as well. I'm just not sure if the CO2 will be a bit lower cost or not.

Budget is somewhat flexible, but ideal would be less than $200.

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diachi said:

Something like this may do you then:

40W CO2 Sealed Laser Tube 850mm | eBay

Would still need a power supply and some water cooling equipment to go with that.

Ships from the US so that's always nice. Probably still cheap Chinese quality though.

Another possible solution: Laser Diode Pumping CW BAR Coherent FAP 25 Watt Burn High Power | eBay

Several members on here have similar diodes, perhaps someone would be willing to part with one? Again, you'd need a driver and some cooling for that too. And of course, laser safety glasses. That kind of power (either from a CO2 laser or a diode) is serious.

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Rivem said:

I'll definitely have to look into the fiber coupled lasers a bit more. Total cost does look like it'll end up lower. I know the bar diode arrays that are usually in them are occasionally good deals on ebay. Definitely will have to get good IR laser glasses though. I already worry about my friend's way overspecced green laser enough.

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diachi said:

You *might* be able to get something used for that budget, but that's really pushing it. I seriously doubt you're going to get anything new for that kind of price though, even from China. The cheapest I can seem to find a new 40W tube is about $250-300 - without a power supply or anything else. A certified pair of laser safety glasses can cost nearly as much as your entire budget.

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Rivem said:

That's what I've found. Just want to see how low I can get the cost. I definitely don't need new, and the system should be self-contained, so I'm not too concerned about high-end safety glasses.

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diachi said:

What do you reckon is the minimum power you can use?

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Rivem said:

I'm thinking around 10 watts. Maybe down to 5.

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ionlaser555 said:

You can get a 20W co2 tube that's 45cm long , they show up on ebay now and then , I paid 150USD for a 20W tube & PSU .

On the goggles side of thing , cheap 50p polycarbonate work perfectly well against co2 lasers , Nothing else ONLY co2 lasers .

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