Homebuilt 3-5W Copper Vapour Laser System

[diachi]

Wow :drool:, I am very impressed LaserBuilder. The fact you managed to get the 578nm line going as well. Good job, +rep from me. :beer:

As far as I understand it's not particularly hard getting the 578nm lasing too. The large bore diameter and high gain of copper vapor lends itself well to easy alignment. You can even get these lasing without an OC mirror, or sometimes no mirrors at all.

This used a 2.5 cm diameter quartz tube in a standard lab oven, 30 cm long active region. The rest of the tube was constructed of Pyrex using standard quartz-to-Pyrex transition seals (usually rings of 6 different glasses in series) with Pyrex stems and tubular aluminum electrodes. Like the first desgin the cavity used planar mirrors and they were 1 meter apart. Both lines lased with 1.5 mR divergence, the beam diameter being limited to 1.2 cm by the Brewster windows. It would lase superradiantly without the mirrors. The rep rate was 30 Hz using an EG&G 1802 thyratron and a 0.2 uF cap on the dissociation side and a triggered spark gap and .012 uF cap on the lasing side. No details of the spark gap are given. Both sides charge through 1M ohm resistors and the 4 uH inductor is absent. Minimum voltage for the disassociation pulse is 7 KV and lasing is a 24 ns pulse, lengthened by gain passes between the mirrors. The optimal firing delay is 200 us. This laser operated at a temperature 550 °C using CuI.

https://en.wikipedia.org/wiki/Superradiance

Still impressive of course!

 

[CurtisOliver]

That is cool, almost as easy to lase as a N2.

 

[Laserbuilder]

Yes, it really can lase superradiantly, but the power is low and the beam diverges like a flashlight. An unstable resonator can make beam divergence very low. If the laser is overheated the green line disappears from the lasing process -- only yellow remains. In context of building and operating such a laser it is hard to supply necessary average power for the laser to make it self-heat. If the Cu laser is heated from an other source than gas discharge inside of it -- ordinary nitrogen laser power supply can be used to excite it, even without properly timed double pulsing like for CuCl or CuBr lasers.

 

[CurtisOliver]

It is interesting that you can excite the gas using a standard n2 power supply. I have never looked into building gas lasers, only dpss's.

 

[Laserbuilder]

Yes, I use a standard Blumlein generator but with very high PRR, that makes the laser to self-heat.

 

[diachi]

It is interesting that you can excite the gas using a standard n2 power supply. I have never looked into building gas lasers, only dpss's.

Yep, both HV pulsed power supplies. Although in the case of CuCl, CuBr or CuI you'd get better results with a PSU designed for Copper Halide lasers, with the correct double pulse.

Yes, I use a standard Blumlein generator but with very high PRR, that makes the laser to self-heat.

Is this pure Cu or is it Cu Halide? Heating by the discharge is nice. What's warm up time like? High PRR is nice too and one of the benefits of using a Thyratron ... I've seen a couple of DIY CVLs with low repetition rates, usually using rotary pulse formers, not quite as impressive as yours.

 

[CurtisOliver]

Thanks Diachi. :beer:

 

[Laserbuilder]

Is this pure Cu or is it Cu Halide? Heating by the discharge is nice. What's warm up time like?

This is a pure Cu laser and double pulsing is not needed for it. It doesn't give any benefits according to russian literature. Warm up time is 30-40 minutes, than 10 more minutes to reach maximum power of the output. Moreover, double pulsing is not needed for Cu halide (CuBr, CuCl, CuI) lasers if PRR exeeds 10 kHz.

 

[diachi]

This is a pure Cu laser and double pulsing is not needed for it. It doesn't give any benefits according to russian literature. Warm up time is 30-40 minutes, than 10 more minutes to reach maximum power of the output. Moreover, double pulsing is not needed for Cu halide (CuBr, CuCl, CuI) lasers if PRR exeeds 10 kHz.

Figured it was Cu, figured I'd ask for confirmation.

Only benefit to discharge heated I can think of is not needing an external heater, at the cost of longer warm-up times. So I'd imagine. I don't really have much hands on with CVLs, mostly just reading.

Did not know Cu Halide didn't require the double pulse for higher PRR (>10kHz) - I knew pure Cu didn't need it, but thought Cu Halide always needed it. Interesting!

Thanks for posting, this is a great thread! Will you be doing any more similar projects?

 

[Laserbuilder]

Will you be doing any more similar projects?

Oh, yes of course. I am working on several laser projects and have a big collection of old gas and lamp pumped solid state lasers. Many of them need repairs to make them running, some need refurbishment. I have some completed laser projects that I will post gradually as I get used to this forum and I have loads of projects to complete

 

[CurtisOliver]

I will look forward to seeing your other projects.

 

[Radim]

Oh, yes of course. I am working on several laser projects and have a big collection of old gas and lamp pumped solid state lasers. Many of them need repairs to make them running, some need refurbishment. I have some completed laser projects that I will post them gradually as I get used to this forum and loads of projects to complete

Great, I'm looking forward as well.

 

[diachi]

Oh, yes of course. I am working on several laser projects and have a big collection of old gas and lamp pumped solid state lasers. Many of them need repairs to make them running, some need refurbishment. I have some completed laser projects that I will post them gradually as I get used to this forum and loads of projects to complete

Also looking forward to seeing more from you, keep them coming! This is the sort of content I enjoy the most.

 

[AngelG]

That was really nice !
What was the original usage for this LASER in Russia ? Medical ? Scientific ?
Didn't know that such lasers (Cu) exist. I ask myself, whether based on this technology is possible to exist also Na and Hg lasers.

 

[diachi]

That was really nice !
What was the original usage for this LASER in Russia ? Medical ? Scientific ?
Didn't know that such lasers (Cu) exist. I ask myself, whether based on this technology is possible to exist also Na and Hg lasers.

Hg is certainly possible and has been done plenty of times, by amateurs too, although I've never heard of Na vapor lasers.

Sam's Laser FAQ - Home-Built Helium-Mercury (HeHg) and Other He-Metal-Vapor Lasers

There are many metal vapor lasers out there, Hg, Au, Se and Cd all come to mind. Cd and Cu (Including Cu Halide) were the only ones I can think of that actually saw widespread use commercially. I've owned a couple different HeCd lasers from different manufacturers (Omnichrome, Kimmon). HeSe is an interesting one, it has up to 24 visible lines.

 

[Laserbuilder]

This particular type of laser tube (UL-102) was used in some machinery for microchip manufacturing, generally Cu vapour lasers of higher powers (LGI-202, for example) were used in labs for pumping dye lasers, similar tubes of somewhat lower powers (tubes of KULON series) are used in medicine, for instance in "Yachroma" device. These tubes are commercially manufactured in small quantities by only one or two factories in Russia, and very hard to find, especially in Ukraine. And finding a CVL tube at a low cost is a jackpot for me.