Quantum coherence in a degenerate two-level atomic ensemble for a transition Fe=0⇆Fg=1 -: art. no. 063809

For a transition F-e=0<---->F-g=1 driven by a linearly polarized light and probed by a transverse light, which has two equal circular components and is orthogonal to the linear polarization of the drive field and magnetic field, quantum coherence effects are investigated. Due to the coupling between the drive Rabi frequency and the Zeeman splitting, electromagnetically induced transparency, electromagnetically induced absorption, and the transition from positive to negative dispersion are obtained, as well as the populations coherently oscillating with a pump-probe detuning in the steady state. At the zero pump-probe detuning, the subluminal and superluminal light propagations are predicted. Finally, there exist the large population fluctuations when we vary the pump-probe detuning.