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Thread: X-Cube prism beam combiner

  1. #1
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    Default X-Cube prism beam combiner

    I was looking at pyrostyro's videos on Youtube, and he showed a beam combiner based on an X-Cube.

    https://www.youtube.com/watch?v=yy-vAc6hPig

    (For someone from LPF, he is amazing! Well worth checking out, IMHO).

    I had not seen this before; why not?
    Is there some horrible lack of transmission mojo or something?
    Cubes are super cheap on eBay.

    Anybody worked with these?

    Thanks...Mike
    Runs with Lasers

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    Usually the cube coatings are optimized for other wavelengths or there is mild crosstalk... Some times you get lucky.
    Also you need to height adjust the lasers very precisely, or use 2 fold mirrors per laser to adjust the height.
    AT that point dichros look good.

    Steve
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    When I still could have...

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    Quote Originally Posted by clickamouse View Post
    I was looking at pyrostyro's videos on Youtube, and he showed a beam combiner based on an X-Cube.
    I had not seen this before; why not?
    There are several threads here on PL that talk about using color splitting cubes and trichros to combine 3 lasers into a whitelight beam. As Steve mentioned, the cubes typically have cheap coatings with poor efficiency. The famed Fujinon Trichro (harvested from pro-sumer grade 3CCD video cameras) was quite a bit better, but even so you still had to deal with the alignment issues. In the end dichros are less trouble, and often are equal in cost by the time you add up all the alignment hardware.

    Here's an old picture of one of my original Fujinon Trichros. (This photo is from ~ 2001 or so.)

    Adam

  4. #4
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    These trichroic prisms / x cubes are found in imaging applications like some triple sensor cameras or triple panel video projectors, one for each color channel.
    In these devices it simplifies the optical design as with dichroic mirror setups you have a different path length for the red green and blue channel beams while you want the different colored pixels in the final very wide diverging projection beam to have the same optical propeties.
    With dichros you might be able to put many lenses between each dichro to correct the aberrations of the image beams, but it's simpler, smaller and maybe also cheaper to have the beams the same optical path and do the optical corrections for all colors at once and only once in the final projection lens or camera lens.

    With collimated beams in galvo projectors there isn't this issue so dichros are easier and better to use.

    Another issue is x cubes are mass manufactured for video projectors and aren't available to be purchased a piece at a reasonable price for building a laser projector compared to dichro prices.

    Final issue is there is some slight light leak, so there's a chance two of your collimated laser beams might be shooting directly at each other and potentially damaging the laser source.

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    And weird combining angles.

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    Quote Originally Posted by buffo View Post
    There are several threads here on PL that talk about using color splitting cubes and trichros to combine 3 lasers into a whitelight beam. As Steve mentioned, the cubes typically have cheap coatings with poor efficiency. The famed Fujinon Trichro (harvested from pro-sumer grade 3CCD video cameras) was quite a bit better, but even so you still had to deal with the alignment issues. In the end dichros are less trouble, and often are equal in cost by the time you add up all the alignment hardware.

    Here's an old picture of one of my original Fujinon Trichros. (This photo is from ~ 2001 or so.)

    Adam

    Off topic but you just brought back warm memories with that SP argon. That was my first argon. Mine was only doing 6mW but oh man... 6mW of 488nm goodness! I made "white" with my 10mW HeNe, .4mW 'Green'Ne, and my SP161. Ahhh, memories!

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    I bought a couple of these years back and after seeing losses of something like 40%+ if I recall correctly, I opted out of using them in a projector. If someone wants to take them (cheap), let me know.

    David
    "Help, help, I'm being repressed!"

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    Default wow-- nice mounts.

    .. is that pine... or oak? I use cedar..JK-- very true about memories..
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    Put one in a window and let the sun shine through. Let it reflect off three glasses of water or crinkled foil for a nice daytime lumia. If foil suspend on string so it blows around. Add steering mirrors befor the foil if you want to make the colors overlap

    add a white beam too! And maybe a focus lens to bring the beam together a bit. Add gobo shapes.

    lens before cube and after

  10. #10
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    Quote Originally Posted by dkumpula View Post
    I bought a couple of these years back and after seeing losses of something like 40%+ if I recall correctly, I opted out of using them in a projector. If someone wants to take them (cheap), let me know.

    David
    Some are made for different wavelengths than typical color laser diodes and some appear to have polarizer layers embedded.

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