Stokes Parameters - Alternate Explanation

Alternate Explanation

A monochromatic plane wave is specified by its propagation vector, and the complex amplitudes of the electric field, and, in a basis . Alternatively, one may specify the propagation vector, the phase, and the polarization state, where is the curve traced out by the electric field in a fixed plane. The most familiar polarization states are linear and circular, which are degenerate cases of the most general state, an ellipse.

One way to describe polarization is by giving the semi-major and semi-minor axes of the polarization ellipse, its orientation, and the sense of rotation (See the above figure). The Stokes parameters, and, provide an alternative description of the polarization state which is experimentally convenient because each parameter corresponds to a sum or difference of measurable intensities. The next figure shows examples of the Stokes parameters in degenerate states.