SATURATION BEHAVIOR IN DEGENERATE 4-WAVE-MIXING WITH NONMONOCHROMATIC, NON-LORENTZIAN FIELDS

We report experimental studies of the degenerate four-wave mixing (DFW M) response in weak field (no saturation) and strong field (saturation ) regimes for the case of nonmonochromatic, non-lorentzian fields. The saturation behavior of line-center intensities and linewidths of rovi brational transitions in the nu(3)/nu(2) + nu(4) + nu(5) Fermi dyad re gion of jet-cooled C2H2 are in good agreement with nondegenerate two-l evel saturation models, suggesting that the on-resonance DFWM response is weakly dependent on laser line shape. We find that DFWM line shape s in the weak field regime are determined by the infrared power spectr um and cubic intensity dependence, as illustrated using broadband (0.3 5 cm(-1)) and narrowband (0.04 cm(-1)) infrared radiation. The saturat ion intensity (I-sat(0)) is observed to decrease with decreasing bandw idth, in qualitative agreement with theoretical predictions. (C) 1996 American Institute of Physics.