This paper reports measurements of intensity-induced rotation of the polarization ellipse, and measurements of the self-focusing threshold and its polarization dependence, using an unfocused laser beam in several Raman-active liquids. An attempt was made to determine the nonlinear susceptibility constants in these liquids by correlating these measurements. It is found that the self-focusing formulas for linearly polarized beams are in good agreement with the experiments, but the polarization dependence of the self-focusing threshold disagrees with the corresponding polarization dependence of the nonlinear index changes. A possible explanation for this discrepancy is discussed.

• Received 20 July 1966

DOI:https://doi.org/10.1103/PhysRev.152.149