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Homework Help: Very difficult problem, don't know where to start

  1. Sep 8, 2008 #1
    A 1-mW laser of wavelength 400 nm, is directed into the interferometer. Initially the path lengths of the two arms are identical, so that all the light goes to the detector at the bottom (i.e., there's complete constructive interference of the waves from the two paths).

    b) Now instead a 5-mW laser of wavelength 800 nm is directed into the interferometer (with the mirror M1 at the displacement calculated in part A.
    How much power is detected at D1? ---> 2.5 mW

    c) What is the minimum mirror displacement (not counting Δx = 0) such that the full power of both lasers would appear at the detector?

    You don't need to worry about interference between the lasers, since they have such different colors.

    Can somebody please help me with this? I simply don't know where to start!
  2. jcsd
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