Abstract

Detailed measurements of the self-pumped phase conjugate emission which arises from internal reflections within crystals of BaTiO₃ have been made. Four-wave mixing, possibly enhanced by stimulated photorefractive scattering around loops of light internally generated within the crystal as well as four-wave mixing at coupling regions of a ring cavity set up between diagonal corners of the crystal are two mechanisms which are believed to give rise to phase conjugate beams. An explanation is also given for the unstable effects often observed on the phase conjugate beam and which gives rise to frequency shifts, pulsations and oscillations. The power of the beam incident upon the crystal determines the threshold characteristics for self-pumped phase conjugate emission.

© 1987 Optical Society of America