Laser mirror by degenerate four-wave mixing in a saturable amplifier

A phase conjugate mirror by degenerate four-wave mixing in a saturable gain medium has been successfully operated in a pulsed laser cavity. This mirror works with low-intensity pump beams when they are resonant with the nonlinear medium. The pump beams can thus be delivered by a continuous-wave, frequency stable laser of low power. In such a device, the pulsed laser emission displays automatic frequency locking to the pump waves without cavity length stabilization.