Vectorial phase conjugation via four-wave mixing in isotropic saturable-gain media

Abstract

We study theoretically the properties of transient degenerate four-wave mixing in an isotropic, homogeneously saturable gain medium with interacting beams of arbitrary strength and polarization state. In particular we investigate the ability of the interaction to exhibit vectorial phase conjugation when orthogonally circularly polarized pump beams are used. This mechanism allows the correction of both phase and polarization distortions introduced to an optical beam. Numerical simulations are compared with experiments that use a flashlamp-pumped Nd3+:YAG amplifier and demonstrate good vector phase-conjugate fidelity for both weak and strong probe beams of arbitrary polarization state.