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Parametric down conversion

  1. Oct 7, 2008 #1


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    Do the two photons (signal and idler) created by PDC always have equal energy?
    (Of course, it depends on the Lorentz frame, but I mean in the frame in which the nonlinear crystal is at rest.)
  2. jcsd
  3. Oct 7, 2008 #2


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    They are close to equal, but that is not a requirement of the PDC crystal output stream. It actually follows conservation of energy (you would expect that) and there is a spread of outputs. (The sum of the output frequencies is equal to the input frequency.)

    Here is a good reference that shows the spread of output wavelengths/frequencies in Figure 1:

    Entangled photon apparatus for the undergraduate laboratory
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