Holographic response characteristics influenced by an absorptive diffusion polymerization model in bulk TI/PMMAs.

Dynamic formation of a volume holographic grating is mainly caused by the diffusion polymerization of a photoinitiator in TI/poly-(methyl methacrylates) (PMMAs). Here, we consider the time-dependent absorption coefficient in this material to establish an absorption modulated diffusion polymerization model. An experimental and theoretical investigation in TI/PMMAs with different sample thicknesses (1-3 mm) is presented. It is indicated that the thickness can regulate the holographic sensitivity and constancy in TI/PMMAs. Furthermore, we also examined the dark diffusion process, multiplexed gratings recording, pre-exposure holographic enhancement, and long-term full exposure in TI/PMMAs with different thicknesses to analyze their holographic sensitivity and constancy. It is predicted that, in general, the absorption characteristics in TI/PMMA can be further affected by changing its thickness, thus it is able to satisfy different requirements in high-density holographic memories.