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Thread: 445nm split and recombine beam?

  1. #11
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    sooo... more importantly, why does it matter so much? where are you going to get a red that will have comparable beam specs (aka isnt a flashlight)

    unless your using 660, in which case 1W of 445 is going to be way too much... so just use a pinhole?

  2. #12
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    Lightbulb

    If the process works well enough on these it might work well on the 638nm diodes to get close enough to a watt that could then be added to a quad of 660...

  3. #13
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    Quote Originally Posted by allthatwhichis View Post
    If the process works well enough on these it might work well on the 638nm diodes to get close enough to a watt that could then be added to a quad of 660...
    a watt of 660 isn't very useful for beam shows, its barely visible unless the room is seriously smoked up... and by the time you stack up/combine/knife edge enough of them your beam is going to be pretty big

    and the 638's are looking like they are going to be worse than the giant 650/635 reds so we are back to square one

    the only diodes that give you decent brightness and dont suck are the 150mW 642's... but even then, you would have to combine a bunch to get a decent power, which means stacking beams, which gives you a gigantic beam again... so again, your screwed no matter what

    unless you go all crazy with telescopes, wave plates etc... but all of that is extra losses, and a lot of $$$ and space in your projector

  4. #14
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    Quote Originally Posted by flecom View Post
    a watt of 660 isn't very useful for beam shows, its barely visible unless the room is seriously smoked up... and by the time you stack up/combine/knife edge enough of them your beam is going to be pretty big

    and the 638's are looking like they are going to be worse than the giant 650/635 reds so we are back to square one

    the only diodes that give you decent brightness and dont suck are the 150mW 642's... but even then, you would have to combine a bunch to get a decent power, which means stacking beams, which gives you a gigantic beam again... so again, your screwed no matter what

    unless you go all crazy with telescopes, wave plates etc... but all of that is extra losses, and a lot of $$$ and space in your projector

    i disagree with most things you say there.

    using the correct lens you can get a good beam with red.

    you can get 5watts of red in a 5mm beam, arctos can get 7 watts of 640 in a 5mm beam.

    5mm isnt big
    Eat Sleep Lase Repeat


    Aluminium Optic Mounts

    http://www.laser-man.co.uk/opticmounts/

  5. #15
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    Quote Originally Posted by p1t8ull View Post
    ... then split the ~8x2mm beam to either knife the pair of 4x2mm beams together or use ...
    just a thought, wouldn't it be the fast axis that you want to split, thus splitting the 8x2 mm beam into two 8*1mm beams? Otherwise you just end up controlling the slow axis....

    So my GUESS is that it would be best to first run the beam through two pairs of prisms to first greatly expand the beam (up to 5x) and reduce its divergence before splitting it. So the too fat fast axis is then split into two slimmer beams which are then joined into a single slim beam. Also using a lens with not a too large FL would be better to prevent the slow axis from becoming to big at aperture.

  6. #16
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    Quote Originally Posted by badger1666 View Post
    when i put a splitting mirror anywhere near the beam it
    just muffed up the whole beam
    No idea Chris, mine looked ok so I would need to take a look at your setup to see what could be causing the muffing (whatever the fek that is )
    I don't know about you but I'm done trying this method now anyway, so won't be spending any more time on it TBH.

    Quote Originally Posted by Phredy1 View Post
    Simon:
    Could you put a anamorphic prism pair before the split and another anamorphic prism pair after the PBS? Or is that getting too expensive and too much losses to make it worthwhile?
    The prisms before the PBS would work, but after going through them the beam would be pretty square and low divergence, so the splitting/folding idea will neither work or be neccessary.


    Quote Originally Posted by Phredy1
    Who has gotten a 4mm x 2mm beam (or better) with decent divergence from a 445nm diode? And how did they do it? I have seen a ton of posts on what lens to use and can't really figure who has a solution for the 445nm that works good.
    You'll need more than just a lens, either cylinder lenses or an anamorphic prism pair will need an invite to the slow axis correction party.
    With a 4mm focal length collimator on a single diode and a pair of prisms I am seeing a beam of just over 3mm round with .9mR divergence. The distant spot is a bit of a line but this can easily be squared up with a tiny focus tweak.

  7. #17
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    Quote Originally Posted by flecom View Post
    sooo... more importantly, why does it matter so much? where are you going to get a red that will have comparable beam specs (aka isnt a flashlight)

    unless your using 660, in which case 1W of 445 is going to be way too much... so just use a pinhole?
    The pinhole is my thought as well, I am going yo build a quad and (Knife edge and PBS) then just hit a pinhole to get the beam size down. I will probably loose a lot but hoping to keep about 50% of the power or more and have a 4mm beam. If you are not worried about losses like me why spend a lot of time and money on Glass?

    Larry

  8. #18
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    Quote Originally Posted by andy_con View Post
    i disagree with most things you say there.

    using the correct lens you can get a good beam with red.

    you can get 5watts of red in a 5mm beam, arctos can get 7 watts of 640 in a 5mm beam.

    5mm isnt big
    5mm is fine, but is the 445 even that big uncorrected? I think people here are trying to get 473nm sized beams out of these diodes and I don't see the point...

    My 650's are 5mm which I would consider huge but when doing beams who's going to notice?

    Even with graphics it's not THAT noticeable since the 445 is big and the 532 is also pretty big (1.5w fairly large beam)

  9. #19
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    Quote Originally Posted by Zoof View Post
    just a thought, wouldn't it be the fast axis that you want to split, thus splitting the 8x2 mm beam into two 8*1mm beams? Otherwise you just end up controlling the slow axis....

    So my GUESS is that it would be best to first run the beam through two pairs of prisms to first greatly expand the beam (up to 5x) and reduce its divergence before splitting it. So the too fat fast axis is then split into two slimmer beams which are then joined into a single slim beam. Also using a lens with not a too large FL would be better to prevent the slow axis from becoming to big at aperture.

    For what its worth I agree with Zoof !

    That's what I call konstruktive kriticisme.

    Cheers

  10. #20
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    wow overcomplicated much? lol

    make a tiny hole in a piece of black aluminum, done!

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