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What is meant by the frequency of a single photon?

  1. Jul 2, 2014 #1
    When I think of frequency, I think of something happening per second or per unit time. When light is a wave, I can understand that it has a frequency, but when it is a particle like a photon, what is the interpretation of its frequency? What is occurring per unit time? Or do we associate a frequency with it when it exhibits wave properties instead of particle? Or just based on its energy we say it has frequency related by E=hf?
  2. jcsd
  3. Jul 2, 2014 #2


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    For an operational meaning matching your sense of "cycles per unit time" you can observe the frequency of a single photon by filtering it with a grating of a given spatial frequency (cycles per unit distance) which we can equate to time frequency using speed of light.
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