Nonlinear magneto-optics and reduced group velocity of light in atomic vapor with slow ground state relaxation

The dynamics of resonant light propagation in rubidium vapor in a cell with antirelaxation wall coating are investigated. We change the polarization o f the input light and measure the time dependence of the polarization after the cell. The observed dynamics are shown to be analogous to those in elec tromagnetically induced transparency. Spectral dependence of light pulse de lays is found to be similar to that of nonlinear magneto-optic rotation. De lays up to approximate to 13 ms are observed, corresponding to a 8 m/s grou p velocity. Fields of a few microgauss are used to control the group veloci ty.