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Thread: Point rate and Laser power

  1. #1
    Join Date
    Jan 2007

    Question Point rate and Laser power

    Hi guys,

    I have been thinking, Will the laser power output increase as you decrease the scan point rate?

    Eg: At 30kpps you could have 1 W power from a 2W laser, as you decrease kpps to say 10kpps, your laser has more time to build up lasing and thus have more output power, At 10kpps = 1.5W

    Anybody think this theory might have some truth to it?


  2. #2
    Join Date
    Dec 2006
    Pflugerville, TX, USA


    I suppose so, but how long does it take for the laser to ramp up?

  3. #3
    Join Date
    Jan 2006
    Charleston, SC


    I'm assuming you're talking about a solid state laser here. If we're talking ion lasers and a PCAOM, then no, because the laser stays on all the time and the response time for the PCAOM is incredibly fast.

    But if you've got a diode laser, then it's all up to the driver. If you have a good driver that can keep everything idling at just below the lasing threshold, and can also ramp up to full power very quickly *without* overdriving the diode (not to mention manage the thermal changes at the same time), then you should have the same performance as a PCAOM. (Well, not the same, mind you, since PCAOM's are ridiculously fast, but it will nevertheless be close enough that human eyes won't be able to tell the difference.)

    Now, if you *don't* have a good driver, then you can get some blanking induced power loss when you blank at high speeds. (Some people call this "jellybeaning"; you can search through the posts here on PhotonLexicon and find several threads talking about it.) In this case, the faster you blank the laser, the more power you loose. (And, it follows that if you slow down your scan speed you also slow your blanking rate, and you'll loose less power to jellybeaning.)

    So yeah, if you have a sub-par driver and you blank the laser rapidly, you'll get some power loss. How much power loss depends on the rate you're blanking the laser and how much delay you get from the diode driver.

    But with really good lasers that have proper drivers, this isn't an issue. (Though you will end up paying more for the laser to start with.)


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