Configuration dependence of optical filtering characteristics in backward nearly degenerate four-wave mixing

Backward nearly degenerate four-wave mixing close to the atomic resonance line has been investigated experimentally. It has been found that phase mismatch provides a window factor to the reflectivity that masks the frequency spectrum of the medium and that the line profile depends on the geometrical configuration of the three interacting beams. The capability of obtaining an optical bandpass filter with nearly degenerate four-wave mixing has also been demonstrated experimentally.