Generation of time-reversed wave fronts using a resonantly enhanced electronic nonlinearity

Time-reversed optical wave fronts were generated by degenerate four-wave mixing in rubidium vapor. An extremely large and resonantly enhanced electronic nonlinearity, described by the adiabatic following (AF) model, was responsible for the mixing. The intensity dependence of the AF nonlinear susceptibility was shown to explain the observed reduction in conversion efficiency at high pumping intensities.