Review of four-wave mixing and phase conjugation in plasmas

Four-wave mixing (FWM) in plasmas and its applications to phase conjugation (PC) and plasma diagnostics have been extensively studied. Plasmas have received considerable attention, since they become more efficient four-wave mixing and phase conjugation mediums at longer wavelengths (far-infrared approximately 10 mu m to radiowave approximately 10 m) for which there are few other nonlinear mediums. In addition, FWM shows great potential as a plasma diagnostic. Recent advances in the experimental and theoretical study of FWM and PC in plasmas are reviewed.>