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Thread: DIY copper vapor laser

  1. #1
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    Default DIY copper vapor laser

    I've always wanted to build a laser from scratch. Was considering a dye, N2 or CO2 but the copper vapor laser looked more interesting because of the green/yellow beams. I started reading the repairfaq.com on copper lasers and would go the CuBr/CuCl route. Looks like the PSU is the most difficult build of the project. Has anyone here ever built one?

    thanks
    Jason

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    I have not tried. A number of members own and operate commercial units. The PSU is indeed the most challenging aspect. N2, CO2 and Cu are all gas based. The dye is lamp pumped and so building one of these (I have built and modified a fair number) is somewhat tangential to the long term goal of building a CU laser. If you have not built anything yet, I would advise starting with the CO2 or the N2 as these are much easier and will allow you to develop some skill in the areas that you could later apply to a CU project.

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    As a former CVL owner, and one who spends a lot of time building, fixing, and using gas lasers, the hardest thing to do on a CVL design is get the pulse rate high enough.
    On a cold, low rep rate CVL using iodides chlorides, or bromides, you need 2 pulses ~ 300 nanoseconds apart to get a flash of yellow and green... Using a classical home made power neon transformer supply, this means you need to design your pulse network to be two Pulses fired A,B A,B, A,B with B firing with a 300 nanosecond gap between them. The first pulse heats and disassociates the bromide, the second pulse lases it.

    When you look at this video, the only time he has a pulse of lasing is when his pulse forming network has a ringing pulse or a double pulse. A lot of work for 10 Hz and 2 mW of average power...
    ~
    https://www.youtube.com/watch?v=Z1Q-g57OFHE
    ~

    Without a big HV DC PSU and a Thyratron, the best you can hope for is this:
    ~
    https://www.youtube.com/watch?v=0Ro9QBGwJUo
    ~
    Note the skipped shots, again, he ONLY gets lasing on ringing plasma pulses.
    ~
    Your looking at 500$ just for the helium, or neon, and regulator. Whereas with nitrogen, home made dpss, or flashlamp pumped dye, you have much better shot at getting some output.
    ~

    Steve
    Last edited by mixedgas; 10-05-2016 at 09:12.
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    thanks for the info. After some consideration, I'll start with either a CO2 or N2 laser.

    thanks
    jason

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    I may be living a little vicariously here, but I would suggest starting with the N2 laser. This is my reasoning. There are a lot of YouTube videos available that will step you through the simplest of transverse discharge nitrogen lasers. These are really easy to succeed at. It is also easy to step up the power and rep rate by upgrading the systems once you have completed the basic model.

    You can move from the simplest Blumlein discharge system to much more powerful ceramic capacitor pumped systems that can drive large gas volumes and you can experiment with adding helium buffer gas to improve stability as well as further increase power. You can also modify these larger systems to pump CO2 in a transverse mode and create a CO2 TEA laser by simply changing the gas, windows and mirrors.

    Nitrogen lasers can pump visible dye lasers, so you can get a visible beam from these lasers and at a high enough rep rate the output appears continuous and the beam quality can be very good.

    The longitudinally driven CO2 laser is not that hard to do either, but once you succeed, all you can really do is burn a hole. You can easily do this with a powerful blue diode laser already.

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    Thanks for the info Planters

    I'll take your advice and go with the TE N2 laser, like you said the co2 laser would probably be boring after a while. I like the idea of ceramic capacitors over the Blumlein system, more compact. I don't mind buying a N2 cylinder, I brew my own beer so a stout on nitro sounds good. I'll continue reading the repairfaq.com on the N2 laser to learn more.


    thanks
    Jason

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    Quote Originally Posted by f150trk21 View Post
    Thanks for the info Planters

    I'll take your advice and go with the TE N2 laser, like you said the co2 laser would probably be boring after a while. I like the idea of ceramic capacitors over the Blumlein system, more compact. I don't mind buying a N2 cylinder, I brew my own beer so a stout on nitro sounds good. I'll continue reading the repairfaq.com on the N2 laser to learn more.


    thanks
    Jason
    i've been wanting to build a little N2 laser for ages and ages. please keep us posted with your progress. maybe it will be the kick i need.
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    I did a n2 using a circuit board and tin foil. Hardest part was getting the caps to discharge fast enough and the gap correct.
    Mine was copied from scientific American diy coulumn.

    Could not find article but this is similar. http://jonsinger.org/jossresearch/la...oardlaser.html

    It's a single day build. Next try doping acrylic plastic with a dye and mAking a ring laser. Just kidding. That's like going from a firecracker to a nuke in one sitting. Still you can drive a dye laser. I used rhodamine b. Wear gloves when they say stain they really mean it. I also heard you can last yellow highlighter juice but I never tried it. I was hPpy making t shirts glow. Ps. That was 1980 something.

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    I've been thinking about this a lot.

    One of the problems with the TE N2 lasers, not TEA (atmospheric) as the pulse width requirement for these is just too demanding, is the bulk of the Blumlein circuit and the switching system.

    I like the idea of the row of door knob capacitors on an acrylic box. Use the fine pitch, threaded studs from the capacitors to support the heavy rails inside the box. This permits minute adjustment of these rails for parallelism.

    Charge the capacitors in parallel from the output of a heavy duty ignition coil like I am doing very successfully with the trigger circuit on my flash lamp powered dye laser. Racing auto ignition coils can tolerate 500V x up to 100uF input on the low voltage side and generate 50kV pulses of 20usec duration. This 20 usec pulse duration would be the charging period for the door knobs. The switching is thus at a relatively low voltage and can be accommodated by a solid state or even a mechanical relay.

    I am envisioning a box about 1/2 M long with say 10, 1nF x 40kV doorknobs, UV windows and external, plano mirrors at 100% and 50% reflectivity. With a 10nsec pulse there may be enough time to establish some resonance rather than just the high divergence, super-radiant emission.

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    ... i have one 30+ years old comercial N2 TAE lasers in my basement, which is capable of 200ps short pulses with up to 400kW peak powers and 30 Hz repetition rate - plans to use it for some sort of "nanomachining" or simply for dye pumping tests.

    The laser source is a small box with adjustable blades, the PS is the biger part in the box - here's an image of the part with the laser cavity in the round box on the left:

    http://forums.reprap.org/file.php?13...=TAE-laser.jpg

    Viktor

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