Formation of a Grating of Submicron Nematic Layers by Photopolymerization of Nematic-Containing Mixtures

A submicron, spatially periodic, structure consisting of a sequence of oriented layers of a ncmatic liquid crystal (NLC), separated by isotropic polymeric walls, was obtained experimentally. This was accomplished by polymerization induced by the interference pattern of UV laser radiation in a NLC-containing prepolymer mixture. It was established that such a structure occurs when phase separation and ncmatic ordering are prevented during the polymerization process. These structures are the diffraction elements, whose efficiency is much greater than that of a standard grating of polymer-dispersed liquid crystals [1-4] which is obtained in the same initial mixture. Specifically, a diffraction efficiency of 60-70% was obtained for structures with the period A = 0.2 jam, even in mixtures where a grating with A < 6 |lm cannot be obtained at all by the standard technique.