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Thread: green laser problem help , watch video

  1. #1
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    Default green laser problem help , watch video

    hi
    anyone have any ideas as to whats up with my green laser
    in general use its dim scan it on its own its not to bad, but switch it cw and it chucks out
    300mw
    example video to show whats going on, http://www.youtube.com/watch?v=gnGceaDm8vQ
    any help welcome as i am fed up with the dam thing
    will a tec tune up fix it ??

    thanks

  2. #2
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    Smile

    Quote Originally Posted by badger1666 View Post
    anyone have any ideas as to whats up with my green laser
    in general use its dim scan it on its own its not to bad, but switch it cw and it chucks out
    300mw
    Yep... Blanking-induced power loss. It's a form of jellybeaning, though not the original form for which the term is coined.

    Basically it's caused by thermal instabilities in the cavity, and it is all too common in DPSS lasers (especially the cheaper ones). I had the exact same problem with one of my first 100 mw TTL-only DPSS greens.

    More info here.
    will a tec tune up fix it ??
    It will help, but it may not fix the problem entirely. I'll bet your laser has only a single TEC. As such, it will be difficult to maintain the proper temperature for the KTP crystal while also keeping the diode cool. (The KTP needs to be warm; the diode needs to be cool.)

    A better laser will have a pair of TECs, one for the diode and one for the doubling stage. Those dual-TEC units perform much better under modulation, but of course they cost more too.

    See if you can find someone local to you who is familiar with your laser and is willing to adjust the TEC driver. That should give you at least some improvement.

    Adam
    Last edited by buffo; 08-17-2010 at 17:14.

  3. #3
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    Default tecs

    Hi buffo
    mine has two tecs I have turned down the temps on both
    and it works quiet well now
    Just need to borrow a power meter to fine tune it

  4. #4
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    Quote Originally Posted by badger1666 View Post
    mine has two tecs
    That's good! A dual-TEC unit will perform much better under modulation (once you get the TEC drivers dialed in correctly).
    I have turned down the temps on both and it works quiet well now
    Remember that the KTP needs to be warm - hot even - for maximum efficiency.
    Just need to borrow a power meter to fine tune it
    Surely there is someone in the UK that can help? (Maybe take it to the next UKLEM?)

    Adam

  5. #5
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    Default

    Just don't adjust the TEC's too far, they are a bitch and a half to adjust from scratch. I still haven't found the perfect setting for my single TEC laser, but it's working OK for the moment until I can find more time to fiddle with it again.

  6. #6
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    Default

    To me it looks indeed that your green laser has some serious problems that are probably temperature related. This is probably also why you did not get the maximum output when using your laser with the FB3 package. See this topic: Pangolin laser not perform at maximum?
    Now I have seen how bad your laser works it is all clear for me. If you need some help with temperature tuning send me a PM. I have tuned quite a lot of lasers in the past.
    http://www.collimated.com/Documents/...imated_PL3.png
    Official Pangolin European Service & Repair Centre
    Authorised Distributor KVANT
    Please visit my webshop --> www.laserwebshop.com

  7. #7
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    Thumbs up Kudo's to Francesco for offering to help!

    Hey Badger;

    I can personally vouch for Francesco's skills. He can definitely improve your laser.

    Adam

  8. #8
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    Default francesco

    Buffo I know how good francesco is I see him work at the last uk meet
    he sent 90% of it tuning peoples lasers for them:
    He does know his stuff

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