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Thread: OOPS, Won't do that again....

  1. #1
    Join Date
    Mar 2006
    Location
    Ottawa, Ontario, Canada
    Posts
    489

    Cool OOPS, Won't do that again....

    I finally got a chance to do some preliminary testing of my Lumonics Lightwriter industrial ND-YLF Laser. I discovered the unit has a laser diode On-Time of 7,159.05 hours and a shot count of 38,660,864 which means that the lightcartidge will need replacing as it's usually only good for 8,000 hours.
    Without cleaning any optics I decided to see if it still works and used my Ophir DGHH digital laser power meter to measure optical power. It has a sensor head that's supposed to be good up to 10 watts. I ran a First Pulse Calibration test on the Q-Switch which runs the laser diode through a spectrum of various laser diode powers and switching times on the Q-Switch and I ended up burning a hole about 3 mm into the edge of the laser power sensor element. It still works but I certainly won't do that again. Shit the maximum power of this class 4 laser is supposed to be 15 watts with a new laser diode but this one's on it's last legs. I was seeing 8 watts with my meter in CW mode. Note to myself "no more testing laser power with the Lightwriter in FPC mode".
    I'll use a carbon block next time.
    Rick
    Profile Redacted by Admin @ 04.24.2010

  2. #2
    Join Date
    Apr 2006
    Location
    Orlando, FL - USA
    Posts
    1,719

    Default

    That's a pulsed laser. You need to use a power meter (and other optics) rated for the high peek pulses, not only the average power of 15 watts. Pulsed lasers a great for blowing holes in things...

    I am glad you learned this lesson (but sorry you had to learn it this way...). Many people only look at the average power of various lightshow effects, but ignore the "pulsed" aspect of things, which may even exist with non-pulsed lasers in certain applications.

    Best regards,

    William Benner

  3. #3
    Join Date
    Mar 2006
    Location
    Ottawa, Ontario, Canada
    Posts
    489

    Cool

    Hi Bill,

    My Ophir DGHH meter is supposed to be good for CW power and pulsed energy readings but limited to 10 watts by the sensor I was using. I was gambling that the power levels would be low due to the pump diodes being near end of life, but it still packed a lot of energy during the Q-Switch calibration and first pulse suppression process.
    I also have another Ophir analog and digital meter with cooled sensor head capable of reading 300 watts ( a better choice next time ). Carbon blocks are great sacrificial absorbers as well.

    TTYL
    Rick
    Profile Redacted by Admin @ 04.24.2010

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