Transient response of nonlinear magneto-optic rotation in a paraffin-coated Rb vapor cell

Abstract

We study resonant nonlinear magneto-optic rotation (NMOR) in a paraffin-coated Rb vapor cell as the magnetic field is swept. At low sweep rates, the nonlinear rotation appears as a narrow resonance signal with a linewidth of about ``$300$ $\ensuremath{\mu}$G'' ($2\ensuremath{\pi}\ifmmode\times\else\texttimes\fi{}420$ Hz). At high sweep rates, the signal shows transient response with an oscillatory decay. The decay time constant is of order $100$ ms. The behavior is different for transitions starting from the lower or the upper hyperfine level of the ground state because of optical pumping effects.