Phase fluctuations on Raman-enhanced nondegenerate four-wave mixing

We have employed phase-diffusion model to study the effects of laser field correlation on the Raman-enhanced nondegenerate four-wave mixing (RENFWM). The different roles of the field fluctuations have been pointed out. A time -delayed method has been proposed to suppress the thermal background. An en hancement of the ratio between the resonant and nonresonant RENFWM signal i ntensities was found as the time delay is increased when the laser has broa dband linewidth. When the lasers have Gaussian line shape, we also present a second-order coherence function theory to elucidate the temporal asymmetr y behavior of the RENFWM.