Polarization degree of optical waves with non-Gaussian probability density functions: Kullback relative entropy-based approach.

The definition of degree of polarization for non-Gaussian partially polarized light is analyzed. A general framework based on the Kullback relative entropy is developed, and properties that enlighten the physical meaning of the degree of polarization are established. In particular, it is shown how the degree of polarization is related to the measure of proximity between probability density functions and to the measure of disorder provided by the Shannon entropy.