Based on the polarization interference between two four-wave mixing (FWM) p
rocesses, we demonstrate a phase-sensitive method for studying Raman-enhanc
ed nondegenerate four-wave mixing (RENFWM). The reference beam is another F
WM signal, which propagates along the same optical path as the RENFWM signa
l. We have employed this method to study the phase dispersion of the third-
order susceptibility chi((3)) and for optical heterodyne detection of the R
ENFWM signal. (C) 2000 Optical Society of America [S0720-3224(00)01109-7].