Observation of resonantly enhanced degenerate four-wave mixing in doped alkali halides

We describe the first reported observation of resonantly enhanced phase conjugation through degenerate four-wave mixing (DFWM) in doped alkali halides. We also describe the first reported quantitative comparison of the resonant DFWM process in the infrared with the theory of Abrams and Lind [Opt. Lett. 2, 94 (1978); 3, 205 (1978)]. The comparison for small values of alpha0L is shown to be excellent. For alpha0L in excess of 3, experiment and theory diverge because of pump attenuation by the resonant medium.