Self-rotation of resonant elliptically polarized light in collision-free rubidium vapor

Self-rotation (SR) of elliptically polarized light resonant with atoms in a collision-free vapor is investigated experimentally and theoretically. Results of density matrix calculations are compared to measurements of SR on the Rb $D1\mathrm{}$ and $D2\mathrm{}$ lines. It is noted that SR effects involving individual hyperfine transitions are suppressed due to Doppler broadening, and so previously unrecognized effects arising from the interaction of light with multiple hyperfine transitions can become dominant.