Partially coherent bidirectional reflectance distribution data computation for modeling periodic plasmonic structures at infrared wavelengths

•Rigorous Coupled Wave Analysis may be used to predict partially coherent scatter.•An angular Gaussian weighted incident field preserves absorption features.•Non-overlapping individually computed weighted scatter lobes are accurate.•Unit cell expansion is required for angularly broad lobes/low coherence lengths.

A series of methods for employing Rigorous Coupled Wave Analysis (RCWA) to predict bidirectional reflectance distributions for periodic plasmonic surface structures, under partial longitudinal spatial coherence conditions, is presented. Two new methods are presented, which accurately represent the effects of directionally dependent absorption on the profiles of reflected diffraction lobes. Bidirectional reflectance distribution functions may be fit to the resulting bidirectional reflectance distributions, allowing plasmonic structures to be accurately incorporated into infrared scene-rendering and component modeling tools.