Light-scattering limitations for phase conjugation in optical Kerr media

Abstract
It is shown that noise from light-scattering fluctuations inherent in an optical Kerr medium sets a lower limit on the incident probe power required to achieve meaningful phase conjugation by four-wave mixing. For visible wavelengths and room temperatures, we determine that about 10 μW of probe power is needed to obtain a signal-to-noise ratio of unity in the conjugate wave for reflectivities that are less than or near the first oscillation condition.