Pressure and power dependence of the optically heterodyne Raman-induced Kerr effect line shape

The effect of pressure and laser power on the high-resolution spectra of co mmonly available gases is studied with the help of the optically heterodyne Raman-induced Kerr effect (OHD-RIKE). The results show the expected pressu re dependence of the spectra, but the effects of saturating laser power are different from previous similar studies employing other four-wave mixing t echniques. In OHD-RIKE no observable sign of saturation such as power broad ening, saturation dips in the line center, or deviation from a linear depen dence of the signal strength with laser intensity was observed for several orders of magnitude greater intensities than previously reported for the sa turation intensities in coherent anti-Stokes Raman spectroscopy (CARS). Sat uration is therefore not the ultimate limit of sensitivity for OHD-RIKE. Th is may be an advantage of RIKE in comparison to other coherent Raman techni ques. [S1050-2947(99)09105-2].