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Thread: Pulsing on 25 mW Green Laser?

  1. #1

    Default Pulsing on 25 mW Green Laser?

    I have a 25mW Leadlight laser pointer. I am very impressed with it. One of my friends is an electrical engineer. He claims that it would be easy for him to rig up some sort of additional circuit board that would give the laser a “pulsing” feature.

    If I pulse this laser at a rate of say .25 seconds on, .25 seconds off, will that satisfy the “1 minute on, 1 minute off” rule of thumb? If so, theoretically then, I could leave the laser pointer on in this pulsing state for extended periods. Also, I assume that would extend battery life. Does anybody have any opinions about my assumptions? Thank you very much.


  2. #2

    Default Re: Pulsing on 25 mW Green Laser?

    sure, you could do this. Or you could turn it back down to 5mW (180mA or so) and run it continuously, too.

  3. #3
    Flashaholic jkaiser3000's Avatar
    Join Date
    Oct 2005
    Caracas, Venezuela

    Default Re: Pulsing on 25 mW Green Laser?

    Generally speaking, pulsing the laser means very short duty cycles, say 20 hz minimum (most often than not it's meassured in khz). That is 20 times on-off cycles per second. Otherwise it would flicker very noticeably.

    On the other hand, you have to remember it's not only the laser diode that warms up, but also the crystal assembly, and with this short duties, it may not have enough time to cool down. So, my advice would be, if you want a pulsed laser, go ahead, but keep the duty cycles intact to prevent any damage. (pulsed lasers do produce some nice effects when swept across a screen )

    Just my thoughts

  4. #4

    Default Re: Pulsing on 25 mW Green Laser?

    Thank you very much for the responses, guys.... Sorry to take so long to get back here.

    In regards to

    "sure, you could do this. Or you could turn it back down to 5mW (180mA or so) and run it continuously, too."

    This comment is a bit confusing to me - This is the 25mW product that AtlasNova sells. I assumed it was a true 25mW product - I am not technical enought to know how to take apart these pointers - are you saying that this is just a modified 5mW pointer that has been "turned up". If so that would be news to me and I would be concerned as to what kind of future problems this would cause. So far, mine seems to work fine.


  5. #5

    Default Re: Pulsing on 25 mW Green Laser?

    Yes I believe those are all modified, though I think he selects those that are stable to sell to people so this should not be a problem really.

  6. #6

    Default Re: Pulsing on 25 mW Green Laser?

    The atlassnova lasers aren't 'turned up' by him, but many come from the factory at max. diode current spec, and those are his good ones. Of those, some have better crystals than others, and those are his really good ones. What you need to be concerned with is the ability of the laser to dissipate heat - enough heat to keep up with the pump diode and KTP.

    A start would be for your EE buddy to measure the battery current. A laser pointer of that form factor is capable of continuous operation at about 180 mA current draw. At 320 mA, you'll want to observe the mentioned duty cycle. Shorter pulses actually are better than longer ones because the KTP will remain more efficient over the pulse duration. Only you can determine the optimal duty cycle - use the diode meter method in a jig to hold the laser and diode steady. Although inaccurate for power measuring, it will allow you to monitor the brightness of the pulses and to see if they are dimming over time. If so, your duty cycle is too great.

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