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What is the range of optical frequecy?

  1. Oct 29, 2014 #1
    I see the term o"ptical frequency" in some articles. From Wikipedia I read that it means the whole EM spectrum. But something says to me it may be only the visible part of the spectrum. Now, which definition is correct?
  2. jcsd
  3. Oct 29, 2014 #2


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    Frequency is a term that applies to all waves. Electromagnetic radiation, including visible light and all the rest of the spectrum, is waves, so the whole spectrum has frequency, but "OPTICAL" frequency would seem to me to be limited to the visible spectrum but perhaps not.

    The term "light" is often used as a stand-in term meaning all electromagnetic radiation, so maybe this is the same kind of loose usage.
  4. Oct 30, 2014 #3


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    There is no exact definition of "optical", but it generally refers to frequencies where you can use conventional optical elements (mirrors, optical fibers etc) to guide the light. From a practical point of view this means infra-red to UV.
    At frequencies lower than that you need to start using antennas etc (although there is a cross-over region in the far infrared where one can use quasi-optical elements), and at higher frequencies it is very difficult to make lenses etc.
  5. Oct 30, 2014 #4
    Thanks. Quite useful! :)
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