Investigation of high reflectivity optical phase-conjugation in BaTiO3

In this paper we present optical phase-conjugation based on the degenerate four-wave mixing (DFWM) arrangement in photorefractive crystal. The 532nm beam from a low-power Nd:Yag laser was split to form two counter-propagating pump beams and one probe beam in the DFWM geometry. Experiments were carried out by varying the parameters (angle of separation between the forward-pump and the probe beam, writing beam intensities) that influence the phase-conjugate beam reflectivity. High reflectivity optical phase-conjugation is hereby reported for low-power lasers. The dependence of phase conjugate reflectivity on signal to pump ratio (in) and forward to backward pump ratio (q) have been investigated experimentally.