Distinctive Properties of Lasing with Dye-Doped Liquid Crystals at the Planar Alignment of a Helical Structure

Abstract

This review focuses on the deliberate study and develop of the most atypical members of the laser family, which use dye-doped matrixes on nematic and cholesteric liquid crystals (LCs). The cause lies in their strengthened light scattering, which can be partially overcome by forced alignment and subsequent light amplification. Their attraction remains due to LC birefringence, which changes under a small outside electric field. Therefore, this review considers the lasing features of dye-doped LC lasers with tunable wavelength oscillations at recording flashy reflective Bragg gain gratings of variable spatial periods in crossed pumping beams. The second approach of lasing oscillation affords steady-state chiral reflective Bragg gratings. Lasing in both approaches is passably described in the frame of coupled wave theory. According to this theory reproducible one-mode oscillation occurs when modifying chiral gratings. Lasing on an induced nematic LC with deeper modulation index refraction revealed the additional spectral state of the LC: the state of a photonic crystal. The existing lasing models need to consider the attributes of the LC photonic crystal, such as the bandgap.