Nonlinear magnetooptic effects in a J = 1 to J' = 0 transition

Magnetooptic effects have proved to be powerful tools in linear spectroscopy. Clear and systematic experiments on the influence of intense monochromatic light fields, however, do not seem to have been performed up to now. The authors give evidence of the existence of nonlinear versions of the Faraday effect and the Voigt effect. They can occur in very low magnetic fields, corresponding to Larmor frequencies in the kilohertz range, at modest laser powers. The experiments have been performed in the 570.7 -nm line of Sm 152, which corresponds to the 4f/sup 6/6s/sup 2/ /sup 7/F/sub 1/-4f/sup 6/6s6p/sup 7/ F/sub o//sup o/ transition and are amenable to full theoretical analysis. In the experiments under discussion here a linearly polarized cw single-mode dye laser beam passes a dilute atomic sample and is monitored after additionally passing a crossed polarization analyzer. Two different orientations of the direction of the magnetic field are investigated