Anomalous Brewster effect and evanescent modes at an achiral/chiral dielectric boundary under planar electromagnetic propagation

摘要

Fresnel coefficients are examined for electromagnetic (EM) propagation across an achiral/chiral (ACC) boundary. It is found that upon both transmission and reflection, the incident plane (specifically perpendicularly or s-polarized) wave transforms into two modes (right circular polarization (RCP) and left circular polarization (LCP)), propagating non-collinearly and collinearly for the transmitted and reflected modes respectively. This paper focuses on certain anomalous properties pertinent to the chirality itself which provide novel insights into chiral materials. Thus, it is found that the Brewster effect manifests itself anomalously in this chiral scenario within specific 'bands' of the (dimensionless) chirality coefficient ((kappa) over tilde). Thus, under appropriate chirality, the Brewster angle (theta(B)) and the reflection coefficient profile may be adjusted via (kappa) over tilde tuning, resulting in zero or low reflections under any linear s polarization. The paper also highlights anomalies relative to total internal reflection (TIR), non-complementarity, mode evanescence, and also possible effective negative-index-like behaviour in the chiral material.