Generation of Four Self-Pumped Phase-Conjugated Waves Using Single Photorefractive Crystal

Abstract

A method of generating self-pumped phase-conjugated waves from four signal beams transporting different information using a single crystal of barium titanate is presented. With one pair of signal beams directed on the (100) face of the crystal and the other pair directed on the opposite (100) face, phase-conjugated images were produced according to the relative power of the two beam pairs. Images were produced even when the beams in each pair fully overlapped on the incident crystal face. At high power ratios (e.g., 1:5), no images of the lower-power beams were produced. The absence of fanning loops in the crystal for the lower-power beams indicates that the information was erased due to scattering of the higher-power beams and/or the interaction between the beams in the crystal. The generation of phase-conjugated waves could therefore be controlled selectively by adjusting the relative beam power of the input signal beams.