Formation mechanisms of multiple holographic gratings in spirooxazine doped poly

Multiple holographic gratings were stored in the same location of spirooxazine doped polymer filmsusing peristrophic multiplexing techniques. Accompanied by UV irradiation, three sets of holographicgratings with different directions were recorded and readout by the He–Ne laser (632.8 nm) and theNd:YAG laser (532 nm), respectively. Diffraction efficiency of each grating was controlled almost uniformby adjusting recording time. It was found that the growth rate of the holog