Coherent Control of Hyperfine States and Slow and Fast Light Switching in Ultracold Atoms

We propose a scheme for attaining slow and fast light via coherent control of the hyperfine ground and excited states of an ultracold atomic system. The proposed scheme is theoretically analyzed for the $D_1$ transition of ultracold $^{23}$ Na atoms. The role of field detuning and field intensity on both the population transfer and induced polarization is investigated. It is shown that slow and fast light, with large bandwidth could be obtained in the proposed system. It is inferred that both slow and fast light could co-propagate, pertaining to different optical and Raman transitions. Further, it is observed that switching between the slow and the fast light is achievable by controlling the field intensity, as well as the field detuning.