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Thread: PBS Cubes and 445nm Diodes...

  1. #1
    Join Date
    Jun 2007
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    Lake Geneva, WI.
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    Default PBS Cubes and 445nm Diodes...

    Hey Everyone!
    As some of you may know. I'm constructing a quad blue for a member here and I'm having a little trouble with the PBS. Unfortunately there are no 445nm cubes available, at least that I know of. So, for this project I picked the 473nm PBS cube thinking that the wavelength would be close enough that I would not get too much loss. As it turns out, it is a HUGE problem.

    See, the two beams heading into the cube like this... "=" are reflecting properly off the 45 degree surface just fine and I get transmission of around 90%! Not bad!

    However.... The two beams that are going straight through the cube, like this... "ll" I'm only getting 10% power transmission after cube! HORRIBLE!

    Yes, I checked the polarization and all I can do is just loose more power.

    Now, It seems that Heroic had very good luck, even though some loss but not nearly as much, from the 405nm PBS. I am just surprised that I would be getting this great amount of loss from the 473nm cube.

    Can anyone shed some light (no pun intended) as to why I'm having such great loss from the 743 PBS?

    Thanks!
    Adam

  2. #2
    Join Date
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    Stockholm, sweden
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    Default

    Hi m8.

    I have had some real problems also with the 445nm PBS. One of them is reflecting at 45 really good but the other who is supposed to go straight through has a loss of about 40-50%

    I wrote about it in another post, and will do some real 2time testing today. i thought i was sent the wrong PBS at first but it wasnt..

    DOnt know if it can have something to do with the profile of the beam being to much of a line?

  3. #3
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    Default

    Quote Originally Posted by rfourt View Post

    DOnt know if it can have something to do with the profile of the beam being to much of a line?
    Yeah, that is kind of what I'm suspecting... I'm loosing a lot more than you are though. I input 50mW and only get 5mW out. I'd be critical of the wavelength coating with 50% transmission but I'm not even close.

    Again, Looks like Heroic does well with the 405nm coated cube so......

    Well.. I'm not sure what to make of that...

  4. #4
    Join Date
    Jun 2009
    Location
    Texas, USA
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    Default

    I am also looking for a PBS for 445.
    CT lasers has a 405 and "blue" PBS, but I haven't received a reply as
    to which is better at 445. They did say they were making some for
    445, but don't know when that will be.

  5. #5
    Join Date
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    Quote Originally Posted by 300EVIL View Post
    Yeah, that is kind of what I'm suspecting... I'm loosing a lot more than you are though. I input 50mW and only get 5mW out. I'd be critical of the wavelength coating with 50% transmission but I'm not even close.

    Again, Looks like Heroic does well with the 405nm coated cube so......

    Well.. I'm not sure what to make of that...
    na I think its just the fact that it was not coated for that frequency... dont think it has to do with the beam profile... I send giant | and - beams of 655 through a PBS without issue...

    thats why I am using a pbs to reflect 445 (with pretty good results... losing about 20~40mW out of 1200mW) and pass 473

  6. #6
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    Default

    Click image for larger version. 

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    If you look at this graph from edmunds for example, you'll see that it is very well possible that optical specs can plummet when the wavelength is a little off.

  7. #7
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    I will test my quality Broadband PBS with 445nm tonight and let you know.

    http://store.laserextreme.nl/catalog...products_id/58

  8. #8
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    Quote Originally Posted by mccarrot View Post
    I will test my quality Broadband PBS with 445nm tonight and let you know.

    http://store.laserextreme.nl/catalog...products_id/58
    Did you get a chance to test at 445?
    Or does anyone else have any ideas on a good PBS for 445?

  9. #9
    Join Date
    Jun 2009
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    Default Some info I've found

    Some info I've found:

    420-680nm broadband. 5mm = $265.00, 10mm = $275, 20mm = $325
    http://www.edmundoptics.com/onlineca...productid=2986
    Looks very good at 445, No idea on maximum power.


    450700nm broadband. 12.7mm = $275
    http://www.cvimellesgriot.com/Produc...msplitter.aspx
    Slightly out of range of coating, above is safer bet.


    450-650nm broadband. 90$-120$ depending on size.
    http://www.delnoptics.com/products/?ID=&ID2=80
    Again out of range.


    405nm and "blue" - probably 473nm. 15mm 60$/50$
    https://www.ctlasers.com/purchases/p...ubes-p-50.html
    e-mailed and said both are not great for 445, but will get some for 445.


    So far, it looks like id be spending $325 for an edmund PBS.
    Anyone else know of a good PBS that is cheaper?

  10. #10
    Join Date
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    Herts, UK
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    Default

    As it happens I have a couple of broadband AR coated PBS' on the way to check out from the optics Co. that makes the anamorphic prisms, perf graphs look good but I'll not say anything until I have seen it with my own eyes..
    They land early September and I'll check them ASAP..

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