AZOBENZENE POLYMER-FILMS FOR OPTICAL STORAGE AND HIGH-ORDER DIFFRACTION .1. POLY[4'-BIS(N,N-OXYETHYLENE) IMINO-4-NITROAZOBENZENE SUCCINYL] FILM

The properties of phase conjugated (PC) beam and stable optical storag e in an azobenzene polymer film were studied by degenerate four-wave m ixing. With low-intensity incident waves (peak value of the pulses of the order of W/cm(2)), the PC beam as well as diffraction beams were o bserved and then disappeared after turning off one of the three incide nt beams. When the peak intensities of the incident beams reached the order of 10 W/cm(2), the PC beam did not disappear but decreased to so me extent after turning off the writing beams. As the peak intensities of incident beams increased to the order of 10(3) W/cm(2), diffractio n up to 4th-order was observed. When all of the three incident waves w ere turned on, three groups of high-order forward and backward diffrac tion beams were observed. Turning off two of the three incident beams, the diffraction beams of the other incident beams did not decrease ob viously, i.e., stable optical storage was realized. After the experime nts, brilliant hologram spot was observed and could be maintained over 120 days without obvious change.