Electro-optical switching of volume holographic gratings recorded in polymer dispersed liquid crystals

In this paper, we describe a novel liquid crystal-polymer composite material system which allows fast, single-step recording of volume holograms with diffraction efficiency approaching 100% and narrow angular selectivity. The diffraction efficiencies (DE) are controllable by applied electric fields. We have achieved complete switching of a first-order Bragg diffracted beam into the zero-order with an applied field of ~8 V/μm and 50-100 microsecond response time. Addition of a surfactant octanoic acid lowered the switching voltage to ~5 V/μm. We also recorded reflection gratings in this material system. We have demonstrated image storage and electro-optical readout with these materials. Low voltage, high resolution scanning electron microscopy studies have confirmed that gratings formed in this material system consist of periodic polymer-dispersed liquid crystal planes