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Thread: Is this PBS any good?

  1. #1
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    Default Is this PBS any good?

    Hi guys,

    Could I use this PBS to combine 2 red 660nm beams together to achieve higher optical power output? Just thought I would ask first before I make any stupid decisions. Thanks guys.

    Cheers.

  2. #2
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    Default

    Pulled posting due to me not reading full information.
    Last edited by Jem; 09-05-2007 at 10:09.

  3. #3
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    BE CAREFUL!

    If the item description is accurate, then the auction title is not.

    From the description:

    The coating shows minimum sensitivity to variations in angles of incident and polarizations

    If that's the case, then it's NOT a polarized beam splitting cube, it's a standard beam splitter, and thus will *not* work to combine two beams of the same color.

    Given that the description goes on to talk about the benefits of using the cube over a plate beamsplitter, I'd say it's damn near certain that the cube is nothing more than a standard 50/50 beamsplitter.

    I'll bet the seller put the word "polarized" in the auction title to get more people to look at it. But in the description, it's clear that he's not talking about a PBS cube at all.

    Also, that's a pretty cheap price for a PBS cube. I paid over $120 for mine. (New Melles-Griot)

    Adam

  4. #4
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    Default

    Quote Originally Posted by Buffo View Post
    BE CAREFUL!

    If the item description is accurate, then the auction title is not.

    From the description:

    The coating shows minimum sensitivity to variations in angles of incident and polarizations

    If that's the case, then it's NOT a polarized beam splitting cube, it's a standard beam splitter, and thus will *not* work to combine two beams of the same color.

    Given that the description goes on to talk about the benefits of using the cube over a plate beamsplitter, I'd say it's damn near certain that the cube is nothing more than a standard 50/50 beamsplitter.

    I'll bet the seller put the word "polarized" in the auction title to get more people to look at it. But in the description, it's clear that he's not talking about a PBS cube at all.

    Also, that's a pretty cheap price for a PBS cube. I paid over $120 for mine. (New Melles-Griot)

    Adam
    Hmm...

    That'll teach me to look a bit more carefully at the descriptions before I open my mouth (or type at the keyboard). Well spotted Adam, I have to confess that I was taking things at face value from the auction title.

    Jem

  5. #5
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    DANG . Buffo, you're a little bit too late mate. I just bought the thing . Well, she sold it to me at cheaper price though after I haggle a bit with her. I'll just have to wait and see then to reveal the truth. Initially I had a feeling that there's something wrong with the description. Hence this thread. Anyway, thanks heaps guys for helping me out. I should have been a bit more patient too in the first place .

    If this PBS turned out to be non-polarized, would this one do the job? Man these optics are so expensive.

    PS: Buffo, where did you get yours from?

    Thanks.

  6. #6
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    Hmmm , by their description...I wouldnt buy it..
    Also, It looks broadband...not good for efficiency for what we want them for... very poor in fact. Sorry.

    Not enough info on that second cube , nothing I can find on the net anyway.
    but Im betting it is also broadband.

    Always go for the narrowband laser-line ones..you'll get at least 90 to 98 percent transmission. Those above are probably 50/50.
    "My signature has been taken, so Insert another here"
    http://repairfaq.ece.drexel.edu/sam/laserfaq.htm
    *^_^* aka PhiloUHF

  7. #7
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    Marconi: I've looked at Melles Griot website for their laser line PBS cubes and they only have them in 632nm for red spectrum and mentioned that it would work at around +/- 25nm. Wouldn't that make it efficient only at 657nm in best case scenario? And I wouldn't get the 90%+ efficiency. I might get this wrong as I know nothing about optics . So please correct me if I'm wrong.

    Thanks mate .

  8. #8
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    I didnt see any mention of +/-25nm there..
    But I can tell you we see at least 95 percent transmission
    at 660 with these.
    "My signature has been taken, so Insert another here"
    http://repairfaq.ece.drexel.edu/sam/laserfaq.htm
    *^_^* aka PhiloUHF

  9. #9
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    I actually got the info from here. I guess the reason they're quoting that figure is because of their very high standard (+/- 25nm at 95%+ efficiency) unlike others who quoted +/- 25nm but at 657nm the efficiency is actually only 50% for an example. Well, I trust your word on this since you made your own laser modules and I've heard lots of praises on this forum . So I highly regarded your opinion .

    I never thought PBS would be that expensive . Well, almost everything they sell are very expensive actually.

    Thanks mate.

  10. #10
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    Ah yes, I see that now...
    Still, they work pretty good...And they are the cheapest you will find that work.

    Anything else is a gamble without specs to work with..
    I've been duped there a few times even when provided specs, but were incorrect.
    While hard to find is the old Philips DVD cubes, they were centered around 650.
    But I have not seen any of these for a few years now.

    Too bad Melles still didnt have the 03PBS094 available..
    that one is centered at 670..
    good thing I got a nice batch of those before they discontinued them.

    High transmittance equals less reflected
    Good luck, and watchout for backreflection.
    Last edited by marconi; 09-03-2007 at 19:38. Reason: spelling
    "My signature has been taken, so Insert another here"
    http://repairfaq.ece.drexel.edu/sam/laserfaq.htm
    *^_^* aka PhiloUHF

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