Polarization-tunable chiral nematic liquid crystal lasing

A chiral nematic liquid crystal laser with arbitrarily controllable polarization was demonstrated by combining polymeric cholesteric and nematic liquid crystal films. The lasing polarization states can be continuously varied by applying voltages from 1.25 to 2 V. Right-handed circular polarization is switched to left-handed circularly polarization through -45 degrees linearly polarized states. The trajectories of the Stokes parameters on the Poincare sphere are used to analyze the variation in lasing polarization. The change in polarization is simulated and the simulation agrees closely with the experimental data. (C) 2010 American Institute of Physics. [doi:10.1063/1.3428399]