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Homework Help: Polarization and Azimuthal Angle

  1. Sep 21, 2013 #1
    1. The problem statement, all variables and given/known data

    Determine the state of polarization of the following wave and its azimuthal angle:

    ##E= \sqrt{3} E_0 \cos(kz-\omega t) \hat{x} + E_0 \cos(kz- \omega t + \pi) \hat{y}##

    3. The attempt at a solution

    How do I calculate the azimuthal angle? :confused:

    My textbook only says: "the azimuthal angle is defined as the angle between the plane of vibration and the plane of incidence". Since no diagrams are provided I'm not sure if I understand it correctly... Is this the angle it makes with the x-axis if it is linearly polarized (or if elliptically polarized, the angle of the major axis with respect to the x-axis)?

    I think the state of polarization is linearly polarized since Ey lags Ex by π, right? Also the Ex has a greater amplitude than Ey by a factor of √3.

    Any help is greatly appreciated.
  2. jcsd
  3. Sep 21, 2013 #2


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  4. Sep 22, 2013 #3
    It doesn't give the definition of the "azimuthal angle". I believe it's the angle θ I've marked in the attached diagram. How can it be calculated?

    Attached Files:

  5. Sep 24, 2013 #4
    How do I calculate azimuthal angle for this wave? :confused:

    I know it's not 45° because ##E_x \neq E_y##. Is it valid to use trig like this:

    ##\tan \theta = \frac{E_y}{E_x} = \frac{E_0}{\sqrt{3} E_0} \implies \theta = 30°##
    Last edited: Sep 24, 2013
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