Chiral optical Tamm states at the boundary of the medium with helical symmetry of the dielectric tensor [In Russian]

TL;DR

This paper introduces a new localized optical state at the boundary of a chiral medium with helical dielectric symmetry, characterized by exponential decay and specific polarization properties, with potential applications in nanophotonics.

Contribution

It analytically and numerically describes a novel boundary state in chiral media with helical symmetry, highlighting its localization, spectral features, and conditions for existence.

Findings

The state is localized near the boundary and does not transfer energy along it.

Field penetration is blocked near the photonic band gap wavelengths.

The state’s spectral manifestation depends on the angle between optical axes.

Abstract

A new optical state is described both analytically and numerically at the boundary of a chiral medium with continuous helical symmetry of the dielectric tensor. The tangential wave number is assumed to be zero. The state appears to be localized near the boundary. It does not transfer energy along this boundary and falls off exponentially with the distance from the boundary. The field penetration into chiral medium is blocked at wavelengths close to the helical pitch and corresponding to the photonic band gap. The polarization of light near the boundary has the same sign of chirality as the helical medium. It is shown that the homogeneous environment, or the substrate must exhibit the anisotropic metallic reflection. Spectral manifestation of the state is determined by the angle between the optical axes at the interface. A realistic example is considered at the boundary of a cholesteric liquid crystal and a metal-dielectric anisotropic nanocomposite.