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Thread: can a "notch filter" be used for combining lasers?

  1. #1
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    Default can a "notch filter" be used for combining lasers?

    I was looking for something to combine 593 into a projector but most dichros seem to go from yellow up, or yellow down... I did manage to find a semrock (NF02-594S-25) that is a "notch filter"... basically passes everything BUT 593 +/-25nm and say

    "Ideal for Raman spectroscopy, laser-based fluorescence instruments and biomedical laser systems, StopLine single-notch filters offer high transmission over wide passbands. They offer deep laser-line blocking with OD > 6 for maximum laser rejection, and rejected light is reflected for best alignment and stray light control."

    so if it reflects the "rejected" beam would that mean I could use it as a reflect 593 pass everything else dichro? or am I a moron?

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    I don't know the difference between a notch filter, a monochromator, and a regular bandpass filter, but I think one of these might let you pass 593.5 and reflect everything else...

    Maybe that's the opposite you're looking for, but it would allow for the two beams to combine. You just need the right setup of course.

    http://www.edmundoptics.com/onlineca...=101&PageNum=6


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    In principle you can use this filter BUT these filters are usually specified for 0° incidence. When you tilt the filter to 45° lets say, the band where light is reflected will move to shorter wavelengths and because of the small rejection bandwith it will not be usable anymore. You can use this principle to choose a filter with a longer wavelength rejection band or use a very small tilt only. Usually the manufacturer can tell you how much the rejection band will shift with tilt.
    What also has to be considered is, that these filters are quite thick and will shift the beam which goes trough several mm.

    Greetings
    Andreas

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    everything below and, a lot of those filters for special stuff are combinations of different filters to get to the desired wavelength. they are thick and have several different filters glued together to get the wavelength. And yes most of them are 0 degree.

    you need to ask the ArKr guys if they have anything. DSLjon would be a good place to start.
    and props for getting a real yellow in there!
    chad

    Edit! try one stop laser shop.


    When the going gets weird, the weird turn pro.


  5. #5
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    Shift is proportional to cosine of the angle. If you read the semrock brochure, I'm pretty sure the graph is in there.

    There is Omega Optical, who sells off set lots of overrun and off spec filters on ebay.

    If you call and ask, or PM the VP that does the Ebay sales, I'm sure he might have something that is close or can be tilted. Usually he can find something that comes close to your needs. Just don't expect better then 85% launch with a off spec filter.

    This is the Omega seller: bjomejag

    a crude example:

    http://cgi.ebay.com/Optical-Filter-D...item518f8809eb

    Ealing makes some good ones, as well.

    I have some ones I could run, but I'm exhausted, if you don't find something in a week, I have a 10 nm wide 568 bandpass that might just tilt. My spectrometer is a bit out of cal, but I can try, when I've had some rest.

    Steve
    Last edited by mixedgas; 01-13-2011 at 14:02.

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    Quote Originally Posted by mixedgas View Post
    Shift is proportional to cosine of the angle. If you read the semrock brochure, I'm pretty sure the graph is in there.

    There is Omega Optical, who sells off set lots of overrun and off spec filters on ebay.

    If you call and ask, or PM the VP that does the Ebay sales, I'm sure he might have something that is close or can be tilted. Usually he can find something that comes close to your needs. Just don't expect better then 85% launch with a off spec filter.

    This is the Omega seller: bjomejag

    a crude example:

    http://cgi.ebay.com/Optical-Filter-D...item518f8809eb

    Ealing makes some good ones, as well.

    I have some ones I could run, but I'm exhausted, if you don't find something in a week, I have a 10 nm wide 568 bandpass that might just tilt. My spectrometer is a bit out of cal, but I can try, when I've had some rest.

    Steve
    see looking at the graph from that ebay auction is an example of my problem... everything I have found is either going to reflect from yellow up, or yellow down, nothing is going to reflect *just* yellow

    thats why I was looking at that rather pricy semrock, if you look at the graph it quite literally notches out yellow (25~nm) and leaves everything else alone

    I wanted to put the yellow nearest the scanners but it seems thats not going to be possible...

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    Your wallet has recovered enough to add yellow to that beast of your's? And a notch filter?
    Love, peace, and grease,

    allthat... aka: aaron@pangolin

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    lol ya right! I wish

    no I got one of those 50mW 593's from eBay and I am looking at making a (low-ish power) 6 color graphics/lumia projector

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    Depending on the rest of your setup, wouldn't a PBS do the job here? If your yellow isn't a fat beam maybe knife edge it in there, not pretty but should work sufficiently.

    Ahh..that 593nm sucker must have cost a small fortune?
    Last edited by Solarfire; 01-13-2011 at 22:42.

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    $500

    and no a PBS would not work since I would need a PBS to combine 445/473 preferably before the yellow

    unless I used a broadband waveplate before it... but that seems a bit excessive

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