Anomalous Level-crossing Resonances in Rb Vapor Cells with Buffer Gas

SummaryThe ground-state level-crossing resonance, or Hanle resonance, in atomic vapors are widely used for atomic magnetometry. In this paper, we report observations of anomalous level-crossing resonances for Rb vapor in a buffer-gas cell. By optically pumping alkali atoms with a ring-shaped laser beam and detecting the spin polarization in the hole of the pumping light with an off-resonance light, we observe a polarization reversion when scanning the transverse magnetic field around zero. Both experiments and simulations are demonstrated.