Theorems on complete electromagnetic coherence in the space-time domain

Abstract

Making use of a recently introduced degree of coherence of random electromagnetic fields, we show that some well-known results on second-order scalar coherence theory in the space-time domain hold within the electromagnetic context as well. In particular, we prove that for statistically stationary electromagnetic waves the following three properties are equivalent: (i) the field is completely coherent in the space-time domain, (ii) the field is monochromatic, and (iii) the electric mutual coherence tensor factors in the two spatial variables and is periodic in the time difference.