Features of Degenerate Four-Wave Mixing in Liquid Crystal Cell in Dynamic Photorefractivity Mode

Features of degenerate four-wave mixing (DFWM) in a nematic liquid crystal cell with photoconductive orienting layers were studied. A method in which three plane waves at angles to each other are applied to the input of the nonlinear medium was used to establish the vector diagram of interaction of the waves. The probe wave interferes with the following two pump waves, which after passing through the cell are reflected in the opposite direction by means of two mirrors. A vector model that agrees well with the obtained experimental results was obtained. Its main difference from the standard DFWM diagram is that the vector of the refractive index grating, on which the wavefront is effectively reversed in the dynamic photorefractive mode, lies at an angle to the vector of the optical interference grating. An experiment in the dynamic photorefractive mode indicated a correction of the spherical and astigmatic aberrations equivalent to the action of a lens with a focal length of < 10 cm.