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Thread: straws as collimator

  1. #1
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    Default straws as collimator

    I was thinking for my lumia project to try and get a natural yellow out of some super bright leds. I figure put in 50W and get 100mw out and that's fine. So my first idea is to use a narrow bandpass filter like 2nm or so, Nothing etalon exotic, and then fine straws as a paralleling element. I'm thinking to use 1mm plastic or metal tubes to make up an element say 2 cm long that fits on top of the led array after the filter. Then use a set of telescopes to narrow down the beam with maybe a spatial filter in the middle that again has a set of straws on the exit (not sure if this even makes sense. maybe skip the spatial. The straws are kind of the spatial.). It isn't going to make a laser tight beam but it might just make a tight enough beam that you could get some kind of interference pattern out of a lumia. Lot cheaper than the alternatives.

  2. #2
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    I don't think the straws will gain you anything.

    Back when the first high power blue luxeon leds came out I tried different ways to get a blue "laser like" beam. The best/ easiest way I found was too remove the plastic lens in front of the led and shove a fiber up against the die. Then just use a lens to focus the other end of the fiber. Because the led die had thin lines that don't emit light, moving the fiber around was needed to find the best output.

    Also, don't necessarily think the higher wattage leds are going to be better. You need to find the led with the highest output per die area.

  3. #3
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    I tried a hollow copper antenna one time and came to the conclusion ..that is; there is no approximation for collimation But good luck, for lumia, you might find an answer by throwing caution to the wind ..
    Last edited by steve-o; 02-07-2018 at 21:40.

  4. #4
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    Or by biting the bullet and buying a yellow laser. Think I’ll go 556nm or 561nm. The 589 looks amber to me. I saw these honeycomb gadgets used by photographers. That’s whT got me thinking. I need to make these anyway for a laminar flow fountain so I’ll play.

  5. #5
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    Considering that a reflective tube would be, roughly, doing the same thing that a fiber would be doing, I would opt to work with fiber. Unfortunately, I don't think you're going to get laser-like output from an LED though. The good thing is, it's cheap to try.

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