Demonstration of a phase conjugate resonator using degenerate four-wave mixing via coherent population trapping in rubidium

A double-Λ system in sodium vapor to be an efficient optical phase conjugator (OPC) is demonstrated. This OPC used a CPT-based grating that produced a conjugate at low pump intensity with high efficiency and fast response time. The sodium double-Λ system corrected high speed turbulence which demonstrates the potential for using an atomic vapor as a nonlinear material. In order to use a CPT based grating on almost any resonant media, the double-Λ system using Zeeman sublevels of a single hyperfine ground state and polarized light are reproduced. This particular experiment used rubidium and found similar performance as the sodium system. This conjunction process work with degenerate laser frequencies which further simplifies the experimental requirements.