Photonic defect modes in cholesteric liquid crystal with a resonant nanocomposite layer and a twist defect

TL;DR

This study investigates the spectral properties of a cholesteric liquid crystal with a combined defect involving a nanocomposite layer and a twist, revealing controllable defect modes influenced by external fields.

Contribution

It introduces a novel analysis of defect modes in cholesteric liquid crystals with nanocomposite layers, highlighting the control of spectral features via external fields.

Findings

Spectral splitting of defect modes depends on nanocomposite resonant frequency.

Defect mode characteristics are influenced by phase jump at the interface.

External fields can effectively control bandgap and defect mode localization.

Abstract

We have studied spectral properties of a cholesteric liquid crystal with a combined defect consisting of a nanocomposite layer and a twist. The nanocomposite layer is made of metallic nanoballs dispersed in a transparent matrix and featuring effective resonant permittivity. A solution has been found for the transmission spectrum of circularly polarized waves in the structure. We have analyzed spectral splitting of the defect mode in the bandgap of the cholesteric when its frequency coincides with the nanocomposite resonant frequency. Defect modes have characteristics strongly dependent on the magnitude and direction of the phase jump at the interface between nanocomposite and cholesteric layers. It has been found that the bandgap width and the position and localization degree of defect modes can be effectively controlled by external fields applied to cholesteric.