Cholesteric Liquid Crystal Mirrors for Pulsed Solid-State Lasers

Cholesteric liquid crystals have been investigated as mirrors in an optical resonator for pulsed solid-state lasers. The out coupling efficiency has been optimized by tuning the reflectivity of the Cholesteric mirror with temperature. Furthermore, the polarizing properties of the helical Bragg-reflection have been used in an electro-optical Q-switched laser instead of the conventionally used combination of dielectric mirror plus polarizer. Pulses of 10 ns duration with peak intensities up to 1 GW/cm2 have been obtained. It is further shown that light-induced changes in reflectivity lead to a passive cavity-dumping and improved transverse beam profile, which may be also of interest for other photonics applications.