Four wave mixing due to the optical kerr effect and Rayleigh-wing scattering

The nearly degenerate four-wave mixing process is considered when the interaction arises through the Kerr nonlinearity and Rayleigh-wing scattering. It is found that the reflection coefficient depends on the product of the pump field strenghts, and that it progressively becomes smaller as the signal beam is detuned from the pump beam. This is in contrast with the electrostrictive case (i.e. the Brillouin type of interaction) where the reflectivity may become large at certain frequency detunings, and may depend on the ratio of the two pump fields, and the phase mismatch.