Four-wave mixing with consecutive coupling of waves in a variant with Brillouin amplification of the reflected wave by a signal

A four-wave mixing configuration with a wave-vector mismatch Δk ≠ 0 is proposed and considered. In this configuration the wave frequencies form a continuous sequence of components displaced by one Brillouin shift. A configuration variant with weak reference waves and a strong signal, which ensures Brillouin amplification of the reflected wave, makes it possible to increase strongly (compared with the four-wave mixing configuration characterized by Δk = 0) the contrast of the reflected wave against the Q-switched background and to increase the reflection coefficient in a mixer with a large transverse cross section.