Efficient phase conjugation of a cw low-power laser diode in a short Cs vapor cell at 852 nm

Up to 50% cw phase-conjugate reflectivity has been obtained with a 30-mW diode laser at 0.85 microm by means of resonant degenerate four-wave mixing on an optically thick, 1-mm-long Cs vapor cell. Self-oscillation of a Fabry-Perot cavity containing this Cs cell is demonstrated.