Interaction of counterpropagating waves and phase self-conjugation in a BaTiO$_3$ crystal

An experimental study was made of steady-state energy exchange between counterpropagating optical waves in a BaTiO$_3$ crystal characterized by gain values in the range $\gtrsim$150 cm$^{-1}$. Stimulated diffusion backscattering by spontaneous "seeds" was observed in a crystal 0.7 mm thick. The conditions for discriminatory phase self-conjugation of continuous radiation by this stimulated scattering mechanism were found theoretically. A steady-state discriminatory phase self-conjugation of He–Cd laser radiation was achieved for Gaussian and speckle pump beams.