Results 1 to 10 of 10

Thread: Best lensing option for dual 445 with cube?

  1. #1
    Join Date
    Feb 2008
    Location
    East Sussex, England
    Posts
    5,242

    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
    Join Date
    Dec 2008
    Location
    Vezon, Belgium
    Posts
    1,017

    Default

    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
    Join Date
    Feb 2008
    Location
    East Sussex, England
    Posts
    5,242

    Default

    Which cylindrical lenses are they?

  4. #4
    Join Date
    Jul 2005
    Location
    Kansas City
    Posts
    211

    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
    Join Date
    Feb 2008
    Location
    East Sussex, England
    Posts
    5,242

    Default

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

  6. #6
    Join Date
    Apr 2008
    Location
    Amsterdam, NL
    Posts
    2,098

    Default

    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
    Join Date
    Feb 2008
    Location
    East Sussex, England
    Posts
    5,242

    Default

    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
    Join Date
    Jul 2005
    Location
    Kansas City
    Posts
    211

    Default

    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

  9. #9
    Join Date
    Feb 2008
    Location
    East Sussex, England
    Posts
    5,242

    Default

    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
    Join Date
    Oct 2010
    Location
    Athens, Greece
    Posts
    1,931

    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...

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •