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Thread: High Power Coherent Laser Diodes on Ebay

  1. #11
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    Dec 2008
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    Thanks for the link, I found a place in my state to get the stuff from. (1 day shipping!)

    How about my idea of running ice water through the laser? Can anyone recommend a place to get suitable lenses to further reduce the line size of this laser? (Ive seen a smaller dot in the youtube videos).

    Thanks,
    Matt

  2. #12
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    Quote Originally Posted by mattrg02 View Post
    Thanks for the link, I found a place in my state to get the stuff from. (1 day shipping!)

    How about my idea of running ice water through the laser? Can anyone recommend a place to get suitable lenses to further reduce the line size of this laser? (Ive seen a smaller dot in the youtube videos).

    Thanks,
    Matt
    You can get a < 40MM plano/convex lens on ebay. Just pick you're focal length.

  3. #13
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    Jul 2008
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    Marysville, WA
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    You may not actuallyl NEED stable cooling for yag pumping, but you will definitely WANT it. As your diode wavelength changes from heat going up or down, your power output will go all over the map. Also, if you built a setup where you can 'tune' the temperature of the diode, you can tune your laser setup for max power. You may lose hundreds of mW's (depending on overall power output) from only a few degrees change in diode temperature. You want the diode to be in the 'sweet spot' of the yag absorption band.

  4. #14
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    Oh yeah, and do you have any schematics of your driver? I would love to build one

  5. #15
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    Dec 2008
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    Ok, so I hooked up my cpu water cooling and something isnt right. Pump seems to work, but the flow seems severely restricted. Do these lasers need a pump capable of high pressure? Liquid does flow, but at a trickle...
    matt

  6. #16
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    Quote Originally Posted by mattrg02 View Post
    Ok, so I hooked up my cpu water cooling and something isnt right. Pump seems to work, but the flow seems severely restricted. Do these lasers need a pump capable of high pressure? Liquid does flow, but at a trickle...
    matt
    Yes, they are restricted internally. 5-15PSI is about the normal operating pressure, very low flow.

  7. #17
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    Dec 2008
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    Ok, so I guess all is fine then? I will hook it back up, and apply power while watching the thermistor value. I wonder why they operate at such low pressure?
    Matt

  8. #18
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    Quote Originally Posted by mattrg02 View Post
    I wonder why they operate at such low pressure?
    Matt
    Because of the micro channeling built into the diode mount.

  9. #19
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    Also make sure your pump is always primed, last thing you want is an air bubble in the pump while it's running, stopping the water flow to your laser

  10. #20
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    Dec 2008
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    Hello,
    Thanks for all the good information! I powered up the laser with the pump running. No good. The temperature didnt rise nearly as fast and it did cool down rapidly, but it is more of a failure than anything. I then added some ice cubes into the coolant tank and this did help out significantly, but only for a short time.

    Im willing to bet I could make a much larger tank (the current one holds like 2 cups max!) and fill it with ice water. This would likely help out some, but it seems that this needs a pump with more pressure or something. I may wind up selling it back on ebay as I already have a coherent FAP800 rated for 40watts at 56A. I stuck it on a single 12V peltier (hot side on a copper heatsink with fan). This keeps the laser COLD even running 30A! Its actually TOO cold! (frost). I am pretty surprised at how well a single peltier works!

    Matt

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