Short wavelength band structure of photons in cholesteric liquid crystals

TL;DR

This paper analyzes the photon band structure in cholesteric liquid crystals at short wavelengths, revealing bound states, dispersion laws, and density of states features, with implications for photon propagation and resonances.

Contribution

It provides explicit expressions for photon spectrum bands and dispersion laws in CLCs, highlighting bound states and their effects on photon density of states.

Findings

Bound states form narrow resonances of photons in CLCs.

Photon density of states exhibits a sharp peak near bound states.

Photons show linear or quadratic dispersion relations depending on permittivity anisotropy.

Abstract

The band structure of photons in cholesteric liquid crystals (CLCs) is investigated in the shortwave approximation. The bound states or narrow resonances of photons in the CLC are formed by the extraordinary waves. The explicit expressions for the spectrum bands and the dispersion laws of photons in these bands are obtained. It is shown that these states describe photons propagating almost perpendicular to the CLC axis. The density of photon states acquires a sharp peak due to the presence of bound states. Near this peak, in the particular case of plasma permittivity, the photons posses a linear or quadratic dispersion relations in the directions perpendicular to the CLC axis depending on the sign of the anisotropy of the CLC permittivity tensor. The resonances in the CLC plate are also described.