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Thread: Dichro for mixing 445 + 462nm

  1. #121
    Join Date
    Feb 2005
    Location
    Switzerland
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    1,390

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    Heya Lari,

    By the way, still not received your package??

    Sebastien

    Quote Originally Posted by catalanjo View Post

    @ " Horizontal arrangement. I believe it's cylindrical lenses"
    Attachment 50613....sounds unlikely (but possible) usually, a horizontal knife edge arrangement will use prisms and almost always, when PBS is being used (highly likely in this case), unless Phil has decided to sell polarised add on modules without mentioning it to his clients...(a big selling point would be missed here).

    Reasoning:
    If you knife edge horizontally, the beam is flat and wide which means unless you add an unnecessary reflection/mirror (not usually recommended unless strictly obligatory for space reasons) to the path of the reflected input into the PBS, the distance from collimator to cyl lens will be different for each side of said beam (cos its WIDE) and gets wider with every beam you add. This effectively eliminates any chance of getting a perfect focus in the farfield, and/or, will increase losses if you use a tight spatial filter.
    (always assuming here that you don't mix upwards into the PBS)

    I think anyway that Phil would prefer you to ask him directly (that way he can say no if he wants to), rather than getting one of his clients (who is probably a friend) to open the lid on a new (virgin/squeaky clean/spotless) set of optics. What's more, I think he relies more on his skill and knowledge, rather than "secrets" to keep himself in business. I am fairly sure, that if you asked him, he would tell you.

    Knowing how someone apparently did something, will not ensure that you can achieve the same results by copying them.
    There is invariably a bit more to it than meets the eye....try painting a Rembrandt,Goya or a VanGogh or even get a machine to do it...it just aint the same!

    However I have to admit, recognising where any possible errors are hiding, is always helpful when trying to design/build something.

    Cheers

  2. #122
    Join Date
    Aug 2010
    Location
    London or Spain depending on the weather
    Posts
    1,381

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    No not yet
    Got a message from Phil via skype and he is "looking into it"
    Cheers

  3. #123
    Join Date
    Aug 2016
    Posts
    17

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    I got one. What diodes should I test it with? I have NUMB44, NDB7875 and NUBM07T.

  4. #124
    Join Date
    Jan 2006
    Location
    Charleston, SC
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    2,147,488,805

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    Quote Originally Posted by Yol8r View Post
    I got one. What diodes should I test it with? I have NUMB44, NDB7875 and NUBM07T.
    All three are quite suitable for testing purposes.

    The NUMB44 is a 450 nm diode. It's near the cutoff for transmission for this dichro, but it should still pass OK. (Unless it gets really hot and the wavelength shifts to the longer side a bit, that is... I don't know how much those diodes shift per degree, but I seem to recall reading that it wasn't much.)

    A good experiment, assuming you have a power meter, is to check the power before and after the dichro and see what sort of losses you get.

    The NDB7875 is 445 nm, which is what I think most people initially planned to use with this dichro. So yeah, it should pass through the dichro pretty well. Again, it would be nice to see some real-world numbers on this if you've got the power meter and the time to check it.

    Your NUBM07T is 465 nm, so it should be easily reflected by the dichro.

    I'd also like to see results from the NDB7675, which is 462 nm, so a bit closer to the cut-off for reflection. For me, at least, this is the other diode (apart from the NDB7875) that I planned to use with my dichros.

    Honestly, the best test would probably be the NUBM44 for transmission and the NDM7675 for reflection, since they are both really close to the cutoff points on the curve, but - alas - you don't have that last diode. Maybe someone else will chime in though.

    Adam

  5. #125
    Join Date
    Aug 2016
    Posts
    17

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    I have a Laserbee AX3, but my drivers are yet to be delivered so I can't power them up just yet. I couldn't test the powerful NUBM44 either way with this sensor.

  6. #126
    Join Date
    Jan 2006
    Location
    Charleston, SC
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    2,147,488,805

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    You don't have to run the diode at full current.

    Run it low enough that you don't overpower your Laserbee and then take your readings.

    Adam

  7. #127
    Join Date
    Jun 2007
    Location
    Monroe, Mi USA
    Posts
    815

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    Hello gang.....Anybody have a pic of their set-up using this B-B Dichro ???

    Measured efficiency ??? I have an email into Lasersystems about supply.....no answer yet ????

    Anyone want to sell one ????? Just contemplating a "Beam on Beam" Four Banger !!

    Thanx,
    CDBEAM
    Beam Axiom #1 ~The Quantum well is DEEP ! Photons for ALL !!
    .
    Beam Axiom #2 ~Yes...As a matter of fact...I DO wear tinfoil on my head !!
    .
    Beam Axiom #3 ~Whe'n dout...Po ah Donk awn et !!
    .
    Beam Axiom #4 ~A Chicken in every Pot, and a Laser Lumia in every Livingroom !!
    .
    Beam Axiom #5 ~"Abstract Photonic Expressionism"....is "Abstractonimical" !!
    .
    Beam Axiom #6 ~ "A Posse ad Essea" ~ From being possible to being actual ...is the beam target !

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