Double phase conjugation in a liquid crystal at 1.5μm for optical beam tracking

Double phase conjugation (DPC) of two nearly opposite light waves has been theoretically and experimentally studied in a nematic liquid crystal with thermal optical nonlinearity. A model for wave coupling in the material with thermal nonlinearity has been analyzed for the DPC threshold conditions. DPC of two mutually incoherent laser beams has been demonstrated in a nematic liquid crystal (NLC) multilayer structure in good agreement with the model. An all-optical beam tracker consisting of such a structure has been built and demonstrated to compensate for beam/reflector jitter.