Phase-conjugate amplification through transverse optical Zeeman pumping in resonant doppler-broadened degenerate four-wave mixing

Abstract

Degenerate four-wave mixing in an inhomogeneously broadened folded three-level system is considered to analyse theoretically the generation of phase-conjugate signals in optically dense media. The counter-propagating pump waves and the copropagating probe and forward pump waves are taken to be orthogonally polarized and interact selectively with the coupled one-photon transitions such that ground-state Zeeman coherence plays the dominant role in phase-conjugate wave generation. It is shown that even in a purely absorptive resonant interaction, transverse optical pumping gives rise to amplified reflection and coupled-mode oscillation, being the required pump intensities very low compared to that needed for saturation of the optical transitions.