Experimental Study of Laser-Induced Orientational Effects in Twist and Planar Aligned Azobenzene Nematic Liquid Crystals

摘要

Laser-induced orientational effects are experimentally studied in BAAB-1005 type azobenzene NLC. Excitation of cis-form of azobenzene was induced by green laser with 0.532 μm wavelength. Nonlinearity was studied by He-Ne laser. 100 μm thick twist-aligned and planar-aligned LC-cells were used in the experiment. During the experiment occurrence of ring pattern was registered on the screen, which was formed during long time (about 10 seconds). Depending on direction of He-Ne laser polarization two types of rings were registered in case of twist-cell. This means that we have two nonlinear mechanisms. In case of planar-aligned LC cell only one type of rings was registered.