Near-field effects on partially coherent light scattered by an aperture

Abstract

We investigate how the near field affects partially coherent light scattered from an aperture in an opaque screen. Prior work on this subject has focused on the role of surface plasmons, and how they affect spatial coherence is well documented. Here, we consider other near-field effects that might impact spatial coherence. We do this by examining the statistics of the near-zone field scattered from an aperture in a perfect electric conductor plane—a structure that does not support surface plasmons. We derive the near-field statistics (in particular, cross-spectral density functions) by applying electromagnetic equivalence theorems and the Method of Moments. We find, even in the absence of surface plasmons, that near-field physics can affect the coherence of the scattered field. The analysis and findings presented herein complement the existing coherence-related surface plasmons literature, and could find use in the design of photonic devices built to engineer spatial coherence.