Diffraction efficiency change in PVA/AA photopolymer films by photosensitive inorganic compound addition

The highest diffraction efficiency (DE) value after illumination and post-curing of photopolymer films were obtained at the SeO₂/Acrylamide (AA) Ratios of AA 3.0 g, SeO₂ 1.0 g and the DE’s were stable values of over 90%. By the addition of SeO₂, the maximum DE at the initial stage of illumination was reached at 300 seconds, which suggests SeO2 slows down the photopolymerization of. DE variation curve for the optimum composition during extendedtime illumination of 9,000 seconds resembles a sine curve due to the combination of the monomer diffusion and the photopolymerization, and the photopolymer film expanded at about 8% after photopolymerization due to monomer migration.