High optical nonlinearity of azobenzene liquid crystals for short laser pulses

Azobenzene liquid crystals (azo LCs) have been proven to possess the highest optical nonlinearity, bounding with photosensitivity, for cw laser beams. We show here that azo LCs are highly nonlinear for short laser pulses as well. Single as well as multicomponent room temperature nematic azo LCs were used in this study for single nanosecond pulses of the second harmonic of a Nd:YAG laser. These compositions demonstrate sensitivity starting from similar to 10 mJ/cm(2) and exhibit response time at the nanosecond scale. The effect of material composition, layer thickness and pulse energy on the nonlinear response of a system of crossed polarizers comprising planar oriented LCs are reported.