Determination of the coherency matrix of a broadband stochastic electromagnetic light beam

The statistical ensemble of a fluctuating, statistically-stationary electromagnetic light beam is presented in terms of a 2 x 2 matrix, so-called coherency matrix. The method to determine such matrix for a quasi-monochromatic light beam has been proposed for many years. In this paper, we demonstrate that the method needs to be only slightly modified to determine the matrix elements of a broadband stochastic electromagnetic light beam, if one uses the representation of statistical wave fields in the space-frequency domain. The implementation of the method is demonstrated, and the coherency matrix measurement is validated using a well-defined elliptically polarized beam