Optically controlled image storage in azobenzene liquid-crystalline polymer films

We report on optically controlled image storage based on photo-induced alignment in azobenzene liquid-crystalline polymer films. Measurements reveal that the polymer film possesses photo-induced birefringence of large magnitude and the characteristic of long-term optical storage. The photo-induced alignment process is used for storing images. The stored image is read from the film placed between two crossed polarizers. It is demonstrated clearly that the alignment of the azo chromophores as well as the stored image can be easily controlled by choosing the appropriate polarization of the irradiating light or by rotating the film.