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Thread: Prism Wanted

  1. #1
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    Default Prism Wanted

    Anybody got a prism going cheap?

    Jim

  2. #2
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    Default

    E-bay has them....

    http://cgi.ebay.com/ws/eBayISAPI.dll...m=120069643818

    Or if you want to do a group buy:

    http://cgi.ebay.com/ws/eBayISAPI.dll...m=120070575395

    I think Spec bought one of these things a long time ago (or he got one from a friend), but anyway they are HUGE. Supposed to be pretty cool though.

    Adam

  3. #3
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    Default

    Those are BEASTs... Shouldn't he be looking for one with AR coating? I read prisms can reflect IR around pretty bad without, but a lot of what I read is hearsay or SciFi... :roll: That's why I "lurk" around here.
    Love, peace, and grease,

    allthat... aka: aaron@pangolin

  4. #4
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    Default

    Allthat:

    You may be right. I didn't think about AR coatings, and now that you mention it, I do think that IR will tend to reflect off a glass surface rather than pass through and be refracted. (The greenhouse effect and all...)

    Still, for Jimbo's purposes it should work out either way. He just needs to separate the visible portion of his beam from everything else and measure it. Then he can compare that reading with one taken before the prism, and if the two are widely different, he knows that the difference is due to IR leakage.

    Adam

    PS: Jimbo - you might want to check with Spec, he might have one...

  5. #5
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    Default

    He could also just buy a dichroic filter that passes the required wanted color and blocks the IR wavelengths. Take some before and after optical power measurements and do some basic math.

    Rick
    Profile Redacted by Admin @ 04.24.2010

  6. #6
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    Rick;

    The prism idea was the cheaper route. A dichro would be great, but it would suck to have to buy an expensive optic that would only be used as a test piece once or twice and then shelved.

    Unless anyone knows of a cheap source of dichros that pass 473 nm and reflect IR?

    Adam

  7. #7
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    Default

    I have ordered another prism so I should get it in a few days.

    Jim

  8. #8
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    Default

    Cool! 8)

    Let us know how the power tests turn out after you get the prism!

    Adam

  9. #9
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    I will do.
    I also bought an electronic shutter off the guy so I'm going to incorrparate that into the projector for safety.

    Jim

  10. #10
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    Default

    If what you want is splitting the laser light into green and possibly IR, why not use a diffraction grating? or a CD for that matter. CD's are used in IR, so it should work fairly well.

    However, if you want the prism for something else, by all means go ahead and grab one, they're fun to work with
    Remember the future?, That'd today, as you imagined it yesterday.

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