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Thread: The Big Green Thread (I'm gonna regret posting this in the morning)

  1. #11
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    Well, that's very nice of you planters. It seems apparent these days that the more minds that we have on a project, the more gets accomplished. Take the 638 "Grail" project. It's all but perfect now. Or, rather it is perfect. On the subject of 532, Z folds and V folds sound interesting and all, but imho the simpler-is-better approach holds for me. Anything that decreases parts count, cost, alignment issues etc seems better. I'm thinking that a lot of research and parts-hunting is going to be the first challenge. I like Steve's idea about cooling the xtal in liquid. Toxic doesn't sound all that great tho lol. If we could find a larger KTP/YV04 xtal instead of the tiny ones found in most of the smaller 532 equipment such as was in my vid, it would be a start, right? You deal with several optics companies directly .. maybe ask them for sources? .. I'll keep looking on the internet for hybrid crystal companies. What size xtal do you think would work? 5x5x3mm I believe I read will output about 1 watt . Maybe something larger than that may be needed.

    --edit-- I was typing when you posted, meatball... do you have any suggestions for said problem?
    Last edited by steve-o; 11-02-2012 at 11:19.

  2. #12
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    OH, Planters, if your in, I'm in.

    There is some sort of magic "hump" that occurs at 2 watts where the price jumps through the roof. Pump diodes go way up.
    Rod lensing is a issue.

    I need to go do some actual work, but I can let my fingers do the walkin through the academic search engines and pull up the Asian standard 3-4 watt design.
    Yep, they standardize them to a degree.

    I have a 5-7 watt Q-switched lamp pumped linear cavity I need to fix. The lamp runs off 220 single, and the 4" arc lamps are 49$ on Ebay. I need to hook up the new lamp supply and test it, but with a 20 hour commute, time is a issue. It has three mirrors in the cavity, a 1064 cavity transfers energy to a resonant 532 cavity. They share one mirror, the 1064 OC is a high reflector at 532. Uses type II LBO.

    I also have a vetted 18 watt V fold design posted in the FAQ. Vetted by a character who knows his business.

    I need 3-4 watts to get back in the Biz, but can't afford it from Asia. I need beam quality, or the ability to get into a fiber.

    My medical friend has some 3-4 watt DPSS modules, they are not for sale. He will however take pics and answer questions. He's had issues with the "bend the steel" and "Indium Solder on Heater" tuning that I have helped him to fix. We can get pump diode and current numbers from him.

    Our lab lasers are not a good ref as they trade pump for mode quality. 8 watts is typically 24-32 amps of dual pump diode.
    I can collect a plot of pump I vs output easy enough.

    I have a 5x5x5 coated chunk of .3% Alpha cut vandate, and I have some ND:YLF designed for DPSS, both oscillator and amplifier.

    Steve

  3. #13
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    24 to 32 amps of current shouldn't be a problem. At the low voltage that the 808 pump diodes operate, 10 or 20 turns of heavy guage magnet/motor wire on the secondary of a transformer should do the trick. I wound one for my argon heater filament that way. It glows bright orange at 2.2V and will do that all day without getting warm.

  4. #14
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    OH, Planters, if your in, I'm in.

    There is some sort of magic "hump" that occurs at 2 watts where the price jumps through the roof. Pump diodes go way up.
    Rod lensing is a issue.

    I need to go do some actual work, but I can let my fingers do the walkin through the academic search engines and pull up the Asian standard 3-4 watt design.
    Yep, they standardize them to a degree.

    I have a 5-7 watt Q-switched lamp pumped linear cavity I need to fix. The lamp runs off 220 single, and the 4" arc lamps are 49$ on Ebay. I need to hook up the new lamp supply and test it, but with a 20 hour commute, time is a issue. It has three mirrors in the cavity, a 1064 cavity transfers energy to a resonant 532 cavity. They share one mirror, the 1064 OC is a high reflector at 532. Uses type II LBO.

    I also have a vetted 18 watt V fold design posted in the FAQ. Vetted by a character who knows his business.

    I need 3-4 watts to get back in the Biz, but can't afford it from Asia. I need beam quality, or the ability to get into a fiber.

    My medical friend has some 3-4 watt DPSS modules, they are not for sale. He will however take pics and answer questions. He's had issues with the "bend the steel" and "Indium Solder on Heater" tuning that I have helped him to fix. We can get pump diode and current numbers from him.

    Our lab lasers are not a good ref as they trade pump for mode quality. 8 watts is typically 24-32 amps of dual pump diode.
    I can collect a plot of pump I vs output easy enough.

    I have a 5x5x5 coated chunk of .3% Alpha cut vandate, and I have some ND:YLF designed for DPSS, both oscillator and amplifier.

    OK, I'm editing my post. I let my fingers do the walking. The cavity is easy. The KTP is easy. The rock of Nd: doped whatever is easy.
    The pump diodes however, are big. Typically 17 watts of fiber pump for 3-4 watts of green. I did not dig enough to find the old side pumped stuff. That looks like the next step.

    2x 2 watts 532 with polarization combine might be economical.

    This makes my lamp pumped medical laser look almost economical.

    Steve

  5. #15
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    Here's 40 watts 808 in fiber Astroguy is selling right here on PL, will that do ?

    http://www.photonlexicon.com/forums/...-Diode-for-CNC

  6. #16
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    Quote Originally Posted by steve-o View Post
    --edit-- I was typing when you posted, meatball... do you have any suggestions for said problem?
    Pulsed operation and/or just q-switching becomes much more common when you begin asking for >5W average power, so I have assumed that its more sustainable thermally and economically as a consequence. The indium foil is certainly required at this point, then thermal control after the fact must be very responsive.


    Steve-o:
    I've got a lovely little switching supply design for pump diodes when the need would arise. Its based on the TI PTH12040W, can regulate up to 50A when you operate in a CC mode with a feedback given by a small op amp circuit. Multiple circuits of the same can be directly paralleled. Should be no need for bringing a transformer for the occasion. You can get all the current your heart desires.


  7. #17
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    Hmm.. sounds good.. I can't buy a lot of stuff for this R/D project tho.. just in it for shizz & grins..

  8. #18
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    I've got 4 of the chips myself. I can't sell them to you since they're samples. But you can get the samples yourself in the same way. Perfect for R&D. Let me know if you want me to send some. I've got the complete circuit as well.. just let me know.

    $10 of parts is lots better than a $900 diode driver.


  9. #19
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    Ok I looked up the TI PTH12040W and they look like neat little modules. They recommend a "loosely" regulated 12V @ xxAmps .Thx Meatball. They appear to be voltage regulated, not current regulated tho .. ?
    Steve- would optic cleaner fluid (Edmunds) work for the "submersible heat sink" idea without f-ing up the coatings/ optics ?
    ..this is getting too complicated already ... ;/ ...
    ps- I ain't doing no q-switch.. never done one, and don't want to .. dammit jim I'm a hobbiest //
    (yes I'm at home now after work and have had toddies ...
    And here's the damn vid if anybody wants to see me make a fool of myself (I'll regret this in the morning ...)
    http://www.youtube.com/watch?v=FPruUSWEx3w

    --Edit--
    PS ---- I just thought this would be easier.. a bigger 808 pump diode and a bigger KTP sandwich super-heatsinked -- I guess it's not going to be that simple.... I was aiming at 1 Watt.. not 5..
    I guess leave it to the experts... That's why the price goes up so much .. I'm not giving up tho ...........
    Last edited by steve-o; 11-02-2012 at 18:29. Reason: pui ..

  10. #20
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    I'm also in it for the grins, but I want to actually see if a multi watt works and I'm willing to spend some money to find out

    I'm not too hot about Q-switching or pulsed as that changes a dangerous laser into a VERY dangerous laser and then there is the whole modulation/ giant pulse/ drilled optics thing. The PBS dual head @ 4W sounds good as 2W is a reasonable middle of the range goal. Also depending on your needs that 2x level of "scaling" is trivial. So I suggest targeting a design for 2W polarized

    Thermal control can be simplified if you trade warm up/down speed for stability and cost. Use a relatively bulky Cu or Al block with an easy to obtain standard TEC closed loop controller; parallel as many as the need determines.

    Probably a stupid question, but why not drive the IR diode with several Flex-mod P3s in parallel ie 3x4A=12A as a quick alternative?

    I don't know about the cooling in liquid. I don't doubt that it can work, but even if toxicity isn't an issue there is containment/spillage and access to optics for alignment. Also, if it does get dirty then how to remove/replace?

    I would go for beam quality from the outset.

    Do any of the common designs include side pumping to avoid expensive fiber pumps and allow slab or stack pumps?

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