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Thread: cylindrical lens pair vs anamorphic prisms?

  1. #91
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    Quote Originally Posted by king4quarter View Post
    Can anyone suggest where I can find a right angle prism with a AR coated hypotenuse? They seem to be hard to find..the hypot side is usually aluminium coated
    Try Lasertack in Germany. High Quality optics they have.
    Their RA prisms are coated with HR dichroic film.
    But are they only reflect or both HR/AR i don't know... Ask them.
    Last edited by epyn; 12-28-2016 at 00:07.

  2. #92
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    I just measured the other axis of the laser beam with a vernia and its 5.6mm at aperture and 3.9mm 4.8meters away so thats -0.354mrad

    As for negative mrad......... Name: banghead.gif Views: 52 Size: 904 BytesName: banghead.gif Views: 52 Size: 904 Bytes
    What you are seeing is the combined effects of divergence (never negative in air) and a convergent focus by the lens.

    Any suggestions as to what I can do to make the beams roughly the same? or make the beams thinner using a telescope or something?
    You are correct, you need to use a telescope. You have a large number of options, but you will usually want the beams to be as similar as possible, especially, most especially, at the distance where you will usually strike the projection surface. Play around with a few lenses and decide how you want to manipulate each beam. A good guide is that you want to fill as much of your scanner mirrors as you can with out spilling off the edges. This will allow you to get the smallest divergence for a given beam. From that point you can decide how you want to modify this best case to match the beams to each other. This will mean you will worsen the divergence of one to match the other.

    If your beams are asymmetrical in cross sectional dimensions, then a one axis (cylindrical) telescope can be used to optimize one axis of a given beam without affecting the other.

    YOU need to experiment because it is impractical for us to give you an exact list of components and their positions without knowing your entire projection layout.

  3. #93
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    You might want to check the green first. If it is a DPSS then typically these have better beam specs than the diodes and if you expand this, the far field spot size may end up significantly smaller than the other two. If you still want to expand, then a slight defocus can fix this.

    Be careful of a diaphragm (as opposed to the pinhole in a spatial filter). These can trim the near field beams, but they can produce some diffraction noise from where the beams strike the edge of the aperture.

  4. #94
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    Quote Originally Posted by king4quarter View Post
    Would this host be sufficient to cool a 1w 520 diode? http://www.ebay.co.uk/itm/231587425428
    NO not sufficient...... unless you live in highlands of Scotland ,AND plan to use it outside, AND only in winter.
    Cheers

  5. #95
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    I think you should read "Jors" excellent post...... http://www.photonlexicon.com/forums/...limator-lenses apart from learning a lot you will find a link to a decent heat sink for your green.
    You will still probably need a fan cos greens get HOT.
    You can also get cheap little thermostat cards from Banggood or fleabay so you can pull the plug on the modulation input if the temp goes too high.

    Cheers
    PS. Find my post and scroll down three!
    Last edited by catalanjo; 03-06-2017 at 16:39. Reason: typos etc.

  6. #96
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    Your welcome.

    Cheers

  7. #97
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    9mm/5,6mm diodes are hard pressed inside those 12mm dia. copper cylinders (12mm copper module)
    Z-bolt heatsink is designed to clamp such 12mm dia module. They also provide small fan to place on top (over those 4 holes)
    http://shop.z-bolt.com/Heat-Sink-for...ules_p_13.html
    https://sites.google.com/site/dtrlpf...s/ndg-1w-520nm

    Quote Originally Posted by king4quarter View Post
    Why are heatsinks for laser diodes so dam hard to find!

  8. #98
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    drill press makes short work of self made mounts.

  9. #99
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    Sorry not numbers, I prefer 1st option but, IMO, its better:
    Pass green, reflect blue, pass green+blue (cyan), reflect red.
    This way you get less loss on red (just one reflection) which usually is the 'weak' one. Also dichros are easier to find for this setup-


    Quote Originally Posted by king4quarter View Post
    Which is better between these two combinations or does it not make a difference?

    Pass green reflect red and then pass green and red reflect blue
    or
    Pass green reflect red and then pass blue reflect green and red

    It feels like a silly question to me but I just want to make sure
    Thanks

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