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Thread: Can somebody check my math?

  1. #1
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    Default Can somebody check my math?

    According to what I think that I've gotten from this technical paper:
    Click image for larger version. 

Name:	EFL and NA formulas.png 
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    ..my calculations are this:
    (..or am I way off base? )

    For my 9x40 mitsu ML520G51 diodes:
    3.5 mm half max beam dia desired:
    40 / 2= 20, 20(sin)= .342, NA =.342
    Now, for the EFL:
    3.5/ 2(.342) =
    3.5/.684=5.117 so,
    EFL=5.117
    So, what is needed is a 633nm AR coated aspheric lens with an NA of .342 and a EFL of 5.117 mm for a decent beam ?


    Thanx in advance,

    -Steve

    PS- the complete article is here: http://www.lightpath.com/literature/...ationNotes.pdf

  2. #2
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    Yep. Spot on.
    I wrote a program for my calculator to do this; as I was forever using it...
    If you use the info in "reverse" you can solve for the slow axis to find the beam size in that axis.

    You can't calculate divergence unless you use the beam parameter product or M^2.
    - There is no such word as "can't" -
    - 60% of the time it works every time -

  3. #3
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    The optima or G2 lens should be fine there....I may have something if you dont nail it down...I have off the wall lenses.
    You are the only one that can make your dreams come true....and the only one that can stop them...A.M. Dietrich

  4. #4
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    Thumbs up

    Thanks Mike and Daniel!
    Mike- Do you have a link to the optima or G2? .. or I guess I could just do a search here..
    Daniel- Could you elaborate on that M^2 thing?
    Thanx again guys.
    Last edited by steve-o; 08-04-2011 at 05:08.

  5. #5
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    Thumbs up

    oops- duplicate post ..
    Last edited by steve-o; 08-03-2011 at 17:21.

  6. #6
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    Thanks Adrian, and welcome to PL! Where are you from?

  7. #7
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    Botsville.... friend or foe busted!

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