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Thread: Alternative to PCAOM

  1. #1
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    Default Alternative to PCAOM

    Anybody got any ideas on quickly modulating the colour of an argon laser without using a PCAOM ? IE using galvos or something ?
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  2. #2

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    Define modulation and define quickly.

    One can blank an argon using a few different types of galvo setups. Yadda has an image here: http://photonlexicon.com/gallery/album41/work2?full=1 of a zfold design thats extremely quick.

    This image here is one I drew a while ago in mspaint Its a "long throw" design. It works like a mechanical lever, the throw distance increase decreases the amount the galvo has to rotate to move the point out of view. I dont have the calculations off hand but you can get it down to less than 1 degree of movement to completely extinguish the beam. As such: it can be pretty damn quick.

    Sadly alignment is absolutely critical as is the stability of the amps, any jitter or "electronic static" getting through will mess it up pretty good.



    As far as "analog" goes without a AOM, I have no idea. Ive theorized about a slit filter that tapers towards the ends to simulate intensity changes but it left really nasty "blooming" and was even more of a bitch to get to work right.

    All this assumes you mean "single color". If you meant selecting a color out of the available ones in the argon laser I saw a neat image that was basically the electromagnetic part of a galvo with a prism attached where the mirror usually is. Then if you wanted to blank that you would need to add the galvo setup again after it.

    Yep, AOM's really make life easy(sorta). I wish I knew a better way.

  3. #3
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    You could use a simple actuator arm with a dichro on the end and have it flip in and out of the beam. You can do this fairly fast....you could have two arms one with a blue, green and no dichro, for 3 different colors .
    Or if your using a beam table, you could set the same situation up but stear the bean through different Dichro paths then off to the sho or back to a scanner pair... Just some thoughts
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  4. #4
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    You could use a simple actuator arm with a dichro on the end and have it flip in and out of the beam. You can do this fairly fast....you could have two arms one with a blue, green and no dichro, for 3 different colors .
    Or if your using a beam table, you could set the same situation up but stear the bean through different Dichro paths then off to the sho or back to a scanner pair... Just some thoughts


    Yes, What Carey said above,

    You can find those dichros mounted on Ledex or similar solenoid switches in various medical lasers like the Lexel 88 to start.
    I might even have some lying around.
    Let me know If you need some and I'll have a look, time for spring cleaning anyhow.

    I much prefer using an AOM for single color modulation over galvos despite the power loss, you can't beat the speed and no aberrations.

    Rick
    Profile Redacted by Admin @ 04.24.2010

  5. #5
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    Okay - so far we've played with using actuators etc, all too slow really. we want fast - as in we want to be able to have multi coloured frames, without buying a pcaom or using aoms.

    Here is something I dug out of my email a while ago, Basically uses two galvos and two dichros, each galvo moves its colour (blue or green) onto or off the pinhole. Depending on how much of each colour is on the pinhole, colour fading can be had.... any thoughts on this ?

    I wonder how hard this would be to set up..

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