The theory of phase conjugation by Brillouin enhanced 4 wave mixing is developed and the effects of phase mismatching and detuning the probe beam from the centre ofathe Brillouin resonance are investigated. Extremely high reflection coefficients (R > 106) are shown to be possible when one pump beam is much stronger than the second, and when the pump beam intensities, the probe beam frequency and the interaction length all take certain critical values.
A. M. Scott, A. M. Scott,
"Phase Matching And Frequency Detuning Effects In Brillouin Enhanced Four-Wave Mixing", Proc. SPIE 0369, Max Born Centenary Conf, (16 June 1983); doi: 10.1117/12.934380; https://doi.org/10.1117/12.934380