Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Where can i buy monochromatic coloured filters(optics):

  1. Jan 28, 2012 #1
    hi there i am looking for monochromatic colored filters like on the picture on the following web page:

    http://en.wikipedia.org/wiki/File:Filter-optics-1.jpg
    (preferably with no reflectivity)

    but i have had no luck trying to find them while looking on google
     
  2. jcsd
  3. Jan 29, 2012 #2

    sophiecentaur

    User Avatar
    Science Advisor
    Gold Member

    You will not find good monochromatic filters. Monochromatic light consists of only one wavelength. Let's assume there is a finite bandwidth of 1% to this filter (and that's not very monochromatic). So the filter would only admit 1% of the light. This would be extremely hard to produce with pigments, which are, essentially, broad band absorbers. Also the manufacturers would need to produce dozens of different ones 'just in case' someone wanted one of any specified wavelength.
    If you really want a source of 'good' monochromatic light then you need a prism or diffraction grating and select light from just one angle. The optics need to be quite good so what I am saying you really want it a spectrometer of some sort. This needs a collimated source with a condenser to ensure plenty of light gets to the grating, a single slit to select the wanted light and some more optics to get the light where you need it. But the same problem arises in that you are chucking a lot of light away.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook