Localized optical modes in a defect-containing liquid-crystal structure adjacent to the metal

The possibility of the existence of localized optical modes with maximum field intensity at the interface between the metal and cholesteric liquid crystal is theoretically grounded. The system comprises a defect-containing cholesteric liquid crystal and a metal layer. It is established that the localization occurs at almost any defect thickness rather than only at the half-wave thickness, at which the loss of the polarization dependence of diffraction reflection and the absence of field localization are observed for the structure without the metallic layer. It is demonstrated that the spectral properties can be controlled by external fields affecting the liquid crystal. At large thicknesses of the cholesteric liquid crystal between the defect and the metallic layer, the spectrum contains the pronounced peaks corresponding to the edge modes. The results obtained open new opportunities for controlling the transmittance spectrum, polarization, and localization of light in optoelectronic elements based on the investigated system.