Effect of phase retardation on defect-mode lasing in polymeric cholesteric liquid crystals

Lasing via a phase retardation defect mode is reported for the first time. The Figure shows the far-field pattern of laser emission realized by inserting an anisotropic nematic liquid crystal (LC) defect layer between polymer cholesteric LC layers. The system mimics the cuticle of Plusiotis resplendens, a beetle, using the birefringence of the anisotropic layer to achieve reflectance greater than the 50% provided by simple cholesteric LC photonic bandgaps.