Localized Optical Modes in Optics of Photonic Liquid Crystals

Abstract
The localized optical modes in chiral liquid crystals are theoretically investigated. Since the cholesteric liquid crystals (CLC) demonstrate common for all chiral liquid crystals optical properties the studying of the problem is performed for the certainty on the CLCs example. A brief survey of the recent experimental and theoretical results on the low threshold distributed feedback (DFB) lasing in chiral liquid crystals as well as new original theoretical data on the localized optical modes in CLC (edge (EM) and defect (DM)) related to the anomalously strong absorption (amplification) of light at the frequencies of EM and DM are presented. An analytic approach to the theory of the EM and DM optics in CLC is developed. The dispersion equations determining connection of the EM and DM frequencies with the CLC layer parameters and other parameters of the defect structure (DMS) are obtained. Analytic expressions for the transmission and reflection coefficients of the DMS are presented and analyzed. As specific cases DMS with an active defect layer are considered, i.e. the DMS with birefringent, absorbing and amplifying defect layers in a perfect CLC structure.

Keywords: chiral liquid crystals, edge modes, defect modes, low threshold DFB lasing