Properties of the degree of cross-polarization in the space–time domain

A definition of the degree of cross-polarization in the space–time domain is introduced which is based on considerations of the correlations of intensity fluctuations of an electromagnetic beam at two points. Some general properties of this quantity are discussed. For the special cases of fully coherent and fully polarized light it is shown that the degree of cross-polarization exhibits a relationship between the states of polarization at the two points.