Defect-mode lasing with lowered threshold in a three-layered hetero-cholesteric liquid-crystal structure

Abstract

A cavity structure for defect-mode lasing with a lowered threshold in three-layered hetero-cholesteric liquid-crystal (CLC) was studied. The cell used for the study consisted of three CLC layers, the middle part of which contained laser dyes and had opposite handedness helix, and a narrower PBG. The study revealed that the defect states emerge and the photonic density of states (DOS) also get enhanced resonantly when the defect mode coincides with the edge mode. The whole system demonstrated certain characteristics - the realization of high-Q cavity, remarkable lowering of the lasing threshold, and the emergence of high DOS.