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Thread: Best lensing option for dual 445 with cube?

  1. #1
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    Default Best lensing option for dual 445 with cube?

    I want to build a cheap dual 45 module putting out about 1.4W (low power so it can remain passively cooled rather than resorting to TECs)

    I have one of P1tbulls cubes on order but am unsure which lense is best suited to cube use. Is it the o-like one?

    I am already using Aixiz 405 glass half threads in my single 445's and have one of the 405-G2 lenses I could test from laser66

    Or do people think that the only way to go with dual 445 is to knife edge and prism pair?

    I don't need absolute beam specs, its only for beam work and not huge venues so higher than average divergence shouldn't hurt too much

  2. #2
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    I tried knife edging two diodes and using the cylindrical lenses, and the beam is really neat! I'd also say lower losses

  3. #3
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    Which cylindrical lenses are they?

  4. #4
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    Default Lens

    I have tried the O-like and aixiz Full thread Glass and they seem to be exactly the same to me. I have been trying to get a knife edge pair to work on the Cylindrical lens sets from the Dr but as he recommends you really need to use the G2 lens for those as you need a smaller initial beam. I have not had any luck with the lens on them

  5. #5
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    Dammit, I thought i might regret selling one of my G2's to catalanjo!

  6. #6
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    It is realy not advisable to use a combiner cube because of the huge difference between the slow and fast axis divergence.

    You should knive edge 2 diodes together and us a prism pair or cylindrical lensed to tame the beam

    The lens you need depends on beam parameters you want.

    With a lens with a FL around the 4mm you will get a 3,5mm beam with 1,2 mrad divergence (after correction optics)

    With a higher FL lens you will get a thicker beam but lower divergence.

    If you are goint to scan the beam with standard 6mm mirrors the best option is the FL 4mm lens.

  7. #7
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    It is realy not advisable to use a combiner cube because of the huge difference between the slow and fast axis divergence.

    You should knive edge 2 diodes together and us a prism pair or cylindrical lensed to tame the beam

    Ok, let me explain my position.

    I already have 2 single 445 modules using just the Aixiz 405 coated half thread glass, which gives me a beam like | which I'm happy with for its intended use.

    If I combine 2 of these with a cube, I will end up with + but no bigger or smaller than the fast axis on my existing ones right?

    Or I could end up with || using knife edges and be done with that, or add prisms

  8. #8
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    After all of my work on a quad I think I am just going to opt to Knife edge and PBS so that aI get a beam like # with the Aixiz lens which is about 5mm beam at aperture and OK Divergence. I have some prisms coming so may go that route. Have you seen this thread , he did some really nice testing and seem to be holding very close to what I have seen.
    http://www.photonlexicon.com/forums/...ion-correction

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    Ok, seeing as its mentioned in that thread, and also lots of other threads, I'm going to bring up the topic of power density again.

    It is said that power density has a major effect on how visible something is - and I will agree, I saw this when going from 1100mW 5mm 650 red to 350mW 2mm 640 red (appeared about the same)

    So I'm unclear why knife edging brings any benefits at all as you are not increasing the power density, you're just doubling the area. Sure, adding prism pairs to a knife edge setup does increase the power density and thats where the gains are.

    If you cube, then you at least gain the portion of the beam that overlaps in the centre of the cross as a higher density area, and therefore it should appear brighter, albeit with a fringe.

    Any comments?

  10. #10
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    Default

    why don't you try to knife edge two diodes, then run it through a prism pair and then use a reverse telescope to shrink the beam and increase power density?

    it is the way i plan to go myself and i dont see why it should not work (puting cost of telescopics aside and extra space needed)

    i understand that this way divergenve will increase, but that should not be so big a pain for beam show use

    just my 2p...

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