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Thread: Cylindrical lenses are 'go'

  1. #11
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    Quote Originally Posted by Laserman532 View Post
    IF they are not coated for AR you can expect on average 4% per surface the beam encounters (no matter what angle you enter it at
    The 4% applies for incidence angle =0 degrees, and it grows until 100% at 90 degrees. Here is a nice plot that shows that, depending on polarisation:



    So for P-Polarization there is no reflection at 56 degrees, which is the Brewster angle, for S-Polarization it is like 15%.

  2. #12
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    Quote Originally Posted by RedlumX View Post
    The 4% applies for incidence angle =0 degrees, and it grows until 100% at 90 degrees. Here is a nice plot that shows that, depending on polarisation:



    So for P-Polarization there is no reflection at 56 degrees, which is the Brewster angle, for S-Polarization it is like 15%.
    i wish i could get 100% reflectance at 90 degrees off of a piece of uncoated plain old glass...that would sure make life much easier not having to deal with all of those nasty coatings come again???

    edit...for all practical purposes normal incidence is generally used for lenses in most applications...(so yes I misspoke in the essence of not wanting to type a lot, )
    Last edited by Laserman532; 07-14-2010 at 08:50. Reason: devel in the details
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  3. #13
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    Quote Originally Posted by Laserman532 View Post
    not to correct the good DR...but as I understand it...the angle at which the beam enters a piece of glass does not affect its reflectance ratio a great deal
    I guess you have been corrected (as have I) But yes, it could be that that transmission chart includes normal surface reflection, which would answer the questions here.

    The focal length of the lenses will be included in the documentation when you receive them.
    Last edited by drlava; 07-14-2010 at 09:06.

  4. #14
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    Quote Originally Posted by drlava View Post
    I guess you have been corrected (as have I) But yes, it could be that that transmission chart includes normal surface reflection, which would answer the questions here.

    The focal length of the lenses will be included in the documentation when you receive them.
    well, technically not...because that chart does not apply exactly to what we are talking about

    edit-keyword with that chart is coefficient
    Last edited by Laserman532; 07-14-2010 at 09:18.
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  5. #15
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    Quote Originally Posted by Laserman532 View Post
    hehe why would anyone want to know the focal length of the lenses unless they were trying to second source them throw the dog a bone for the love of god...he researched them
    It has nothing to do with second sourcing. It has to do with whether the lenses are suitable for a special application or not...

    Quote Originally Posted by Laserman532 View Post
    20mm separation might give you a hint
    Yes, it gives me a hint. But I need the focal lengths to know the expansion rate.


  6. #16
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    RGB, PM sent.

    15

  7. #17
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    OK, I know this is a bit of a silly question, but Pat, for your knife edge kit, would I be able to use one of these kits after knife edging, or will I need one for each diode before the knife edging?
    "TO DO IS TO BE" - Nietzsche
    "TO BE IS TO DO" - Kant
    "DO BE DO BE DO" - Sinatra

  8. #18
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    Quote Originally Posted by Mr.Coffee View Post
    OK, I know this is a bit of a silly question, but Pat, for your knife edge kit, would I be able to use one of these kits after knife edging, or will I need one for each diode before the knife edging?
    so far I hear is one pair after knife edging of two at least...not sure on four...but I suggest you buy my four banger and test it and let me know...I personally have never tried it
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  9. #19
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    Added beamshot photo

  10. #20
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    Quote Originally Posted by drlava View Post
    Added beamshot photo
    Hey drlava, I just did a quick sketch of a tweakable collimator system for these lenses. I assume that you go into the small lens first...the small lens is 3mm wide and 8mm high, will it work no matter which way the diode is rotated?
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