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Thread: RGB collimated unit

  1. #1
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    Default RGB collimated unit

    Hi All,


    I'm looking for a compact RGB collimated unit which outputs a 1-inch, aligned, collimated beam.
    I haven't been able to find an appropriate one.
    Do you guys have any suggestions?
    If you know a supplier or specific company, please send me the link.

  2. #2
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    More detail. One inch square round rectangle. Power divergence use?

  3. #3
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    Quote Originally Posted by kecked View Post
    More detail. One inch square round rectangle. Power divergence use?
    1-inch diameter circular is enough.
    The output should be pretty well collimated.
    I have put together one with adjustable mirrors myself using Thorlabs parts but I need a more compact unit.
    All lasers should have the same polarization.

  4. #4
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    Quote Originally Posted by Tekosh View Post
    1-inch diameter circular is enough.
    The output should be pretty well collimated.
    I have put together one with adjustable mirrors myself using Thorlabs parts but I need a more compact unit.
    All lasers should have the same polarization.

    that’s a weird request. Most people want 1mm not 1 “. What is the application?

  5. #5
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    Nearly all of the commercially-available laser modules will have a beam diameter far smaller than 1 inch. (2 to 5 mm is typical) However, you can up-collimate the beam to whatever diameter you want with a pair of lenses.

    There are two basic arrangements: Galilean and Keplerian. Or you can simply purchase an off-the shelf beam expander from someone like Edmunds (though they will be expensive).

    The advantage of up-collimating the beam is that the divergence will be reduced. So you might start out with a 5 mm beam at 1 mrad and end up with a 25 mm beam at .2 mrad.

    For further assistance, you need to clarify your needs:

    "pretty well collimated" is too vague. What divergence do you require? (Alternately, what are you trying to accomplish, over what distance, with this initial 1 inch diameter beam?)

    "compact" can mean many different things. What are the limiting dimensions for the laser module?

    Other questions that need answering: What optical output power do you require, how will the laser be powered, what sort of reliability is required, and do you care if the beam profile is irregular (multimode diode) or not.

    Adam

    PS: Ignore the attachment below. Forum bug - attachment does not exist.


    Attachment 56205

  6. #6
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    Seems to me he may really want a highly collinear RGB source with individual component modules having similar diameter and divergence and nice round beams that can then be up-collimated. I saw a similar request on LPF. Maybe he thought projector people could recommend better behaved sources than pointer people. That's a lot of alliteration!

  7. #7
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    Only thing I could figure was laser point to point communication or maybe hologr@ms?

  8. #8
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    I figured long distance application too. A holographer would be asking for long coherence too.

    Lots of people interested in full color holography using the silver-halide materials available now, but it's always harder and more expensive than one thinks to get collinearity and color uniformity across an expanded specular beam. I'd imagine that's just as important to someone sending an RGB beam a very long distance.

  9. #9
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    If he went with a Keplerian collimator to increase the beam diameter he could position a spacial filter at the focal point between the two lenses to clean up the beam. That should yield a fairly uniform output with minimal fringing.

    He doesn't mention how much power he needs. If the power requirements are low, he could probably get really good results with a set of single-mode diodes from DTR and one of the single-mode module kits from lasershowparts.com. (Plus the lenses and pinhole for the Keplerian collimator and spacial filter of course.)

    If he needs watts of output then he's either looking at a shitload of single-modes that are knife-edged, or else a multi-mode module with really good optics. Either option will be pricey though if he's looking for identical beam diameter and divergence across all three colors.

    And without more info on what he wants to accomplish, we're probably just pissing in the wind at this point.

    Adam

  10. #10
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    Seeing how he never responded or returned in over two weeks I think we are talking to ourselves. Ps all need to have same polarization. This is more like a confocal microscope thing.

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