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

摘要

We have studied spectral properties of a cholesteric liquid crystal with acombined defect consisting of a nanocomposite layer and a twist. Thenanocomposite layer is made of metallic nanoballs dispersed in a transparentmatrix and featuring effective resonant permittivity. A solution has been foundfor the transmission spectrum of circularly polarized waves in the structure.We have analyzed spectral splitting of the defect mode in the bandgap of thecholesteric when its frequency coincides with the nanocomposite resonantfrequency. Defect modes have characteristics strongly dependent on themagnitude and direction of the phase jump at the interface betweennanocomposite and cholesteric layers. It has been found that the bandgap widthand the position and localization degree of defect modes can be effectivelycontrolled by external fields applied to cholesteric.