Optimization of photo-induced molecular reorientation in azobenzene polymer film

Molecular reorientation of an azobenzene in a polymer film is studied by using polarized actinic beams with two colors. The photo-induced molecular reorientation can be optimized when the polarizations of the actinic light beams are orthogonal. We applied this feature to write a nonvolatile holographic grating in the film. The stored information can be read repeatedly without volatility with the same wavelength as the writing beam.