Ultrafast volume holographic recording with exposure reciprocity matching for TI/PMMAs application.

The range of exposure for which the holographic reciprocity law holds in photopolymers, is mainly dependent on the light exposure intensity and polymerization rate between photo-initiator and monomers. Matching this is the key to improving performance. Characterization of the dependence on diffraction efficiency of the volume transmission gratings on holographic reciprocity matching of TI/PMMAs under different milliseconds with different thickness (1-3mm) has been carried out for the novel high-sensitive TI/PMMA polymers. Diffraction gratings can be recorded in TI/PMMAs under 20ms with the exposure intensity of 115mW/cm2. The physical and chemical mechanism under and after single shot exposure is analyzed which can be divided into three parts, namely, photo-induced polymerization, dark diffusion of photosensitive molecules, and counter-diffusion of photoproducts. Holographic properties of TI/PMMAs of different thickness (1-3mm) under different shingle-shot durations and repetition rates are investigated in detail as well. The diffraction efficiency reaches 67% with the response time of 15.69s. By this way, volume holographic gratings with no reciprocity failure can be recorded under multi-pulse exposure, with high grating strength and rapid sensitivity in TI/PMMAs, which indicates the volume holographic memories have the potential for recording and storing transient information in life and in the military.