Polymer-enhanced diffraction in an azo-dye-doped liquid crystal

Degenerate four-wave mixing measurements were employed to obtain first-order diffraction efficiencies of dye-doped and polymerdye-doped liquid crystals. A sixfold enhancement in the diffraction efficiency (12%) was found for the liquid crystal doped with 1% azo dye and 1% polymer, compared to a 2% diffraction efficiency found for the liquid crystal containing 1% azo dye. Polarization dependence of absorption and diffraction studies, coupled with the absence of two-beam coupling, support a grating formation based on photoisomerization of azo dye molecules, which leads to a reorientation of the liquid crystal phase. (C) 2001 Society of Photo-Optical Instrumentation Engineers.