| 초록 |
Transmission holographic polymer dispersed liquid crystals(HPDLC) is candidated in sensor systems, head-up displays, optical interconnects, and optical data storage. In this study, we attempted to obtain high storage density by controlling the PUA structure and LC with various refractive indices. We performed the holographic transmission gratings by Ar-laser(λ=514㎚) curing of a polyurethane acrylate(PUA) prepolymer composed of PUA oligomer, reactive diluents, photoinitiator dye and co-initiator mixed with the liquid crystal(LC) mixture E7. We controlled the balance between photopolymerization kinetics and LC separation by controlling laser intensity and the ratio of LC contents. To obtain various grating spacings, we changed the intersection angle of the two beams outside the sample. Diffraction efficiency and angular selectivity were measured according to the molecular weight of polyol. SEM studies were performed to determine the morphologies of holographic gratings.
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