Photonic band edge and defect modes in 1D cholesteric liquid crystals

Liquid crystals are transparent optically birefringent materials that have the ability to self-assemble into tunable photonic microstructures. They can be modified by adding chiral dopants, by anchoring on confining surfaces, temperature changes, and by external electric or magnetic fields. Cholesteric liquid crystals (CLCs), which have a periodic helical structure, act as photonic crystals and thus partially reflect light with wavelengths comparable to the period of the structure. Possessing these properties, CLCs can be utilized as resonators or even as micro-lasers if doped with organic dye. In this work, we present the findings of a numerical study of light transmission through CLCs with or without isotropic defect layers in different 1D geometries. We also show numerically calculated photonic eigenmodes and their corresponding Q-factors. Overall, this work summarizes the properties of CLC resonators that could be important for the design of liquid crystal micro-lasers and other soft-matter-based photonic devices.