Analysis of diffracted waves from isotropic chiral gratings

Abstract

AbstractThis paper proposes an analysis method of diffracted waves in isotropic chiral gratings with periodicity in an arbitrary three‐dimensional direction. In this method, the spatial harmonic expansion method applied to the analysis of anisotropic dielectric gratings is extended. By Fourier transform of the periodicity of the chiral admittance, a systematic matrix form is used for rigorous formulation. In the numerical examples given here, calculations are carried out for the density modulated grating in which the relative dielectric constant and the chiral admittance distributions are varied sinusoidally. A coupling between the circularly polarized diffracted waves due to the Bragg condition and an anomalous diffraction phenomenon due to the chiralty of the medium are presented. This coupling is not observed in the case of nonchiral isotropic dielectric gratings.