High-reflectivity phase conjugation using Brillouin preamplification.

We describe experiments in which a weak laser pulse is phase conjugated by using a high-gain Brillouin amplifier in front of a stimulated Brillouin scattering phase-conjugate mirror. We observe phase conjugation with signal energies as low as 3 x 10(-13) J and with a maximum reflection coefficient of 2 x 10(8).