Large Stable Photoinduced Anisotropy and Optical InformationStorage in Poly 4-bis (N, N-oxyethylene) imino-4- nitroasobenzene Succinyl Film by Two-Wave Mixing

Optical information storage caused by photoinduced anisotropy in poly 4'-bis (N, N-oxyethylene) imino-4-nitroazobenzene succinyl film is studied by two-wave mixing. Using Nd:YAG second-harmonic pulses (100ps), grating of orientation of azobenzene molecules is formed in the film by photoinduced anisotropy. Up to third-order diffraction was observed. After turning off one of the two pump lights, the signals remained. When the weaker one of two pump lights was turned off, the intensities of diffraction beams of another pump light almost did not decrease. The information recorded in the film can be 100% maintained for a long time (monitored over 100 days without obvious decrease).