Spatial correlation functions of inhomogeneous random electromagnetic fields

We analyze the influence of an infinite planar perfectly conducting surface on the spatial correlation functions of a random quasimonochromatic classical electromagnetic vector field, based on a TE/TM decomposition of an angular spectrum of random plane waves. The presence of the surface causes the correlation to depend on both the absolute and relative locations of the field points (inhomogeneous correlation). Known asymptotic results for statistically homogeneous random free fields are retrieved as special cases. The analytical results are illustrated with computations for separations that are either perpendicular or parallel to the surface. The correlation distance for any field component exhibits a damped oscillatory dependency on the local center point. A geometric interpretation in terms of fluctuations of correlation cells is given.