<title>Analysis of periodic polymer-dispersed liquid crystal structures for dynamic hologram applications</title>

Abstract

Electro-optical switching of the diffraction efficiency in volume holographic gratings offers the possibility of real-time control and programmability of diffractive optic components. We have recently demonstrated efficient electro-optical control of the diffraction efficiency in gratings consisting of periodic polymer-dispersed liquid crystal (PDLC) planes. We analyze this system as a rectangular index modulation profile, with the low index region being pure polymer, and the high index region consisting of a distribution of ellipsoidal nematic liquid crystal droplets of sub-micrometer size. The results of coupled-wave theory are combined with an analysis of the electro- mechanical behavior of these droplets to model the field-dependent diffraction efficiency. The effects of system parameters on diffraction switching is explored, and a physical interpretation of the switching phenomena in PDLC gratings is elucidated. Insights to the design of practical switchable diffractive optical elements can be obtained from the model.