The effects of degeneracy of atomic levels on single-photon emission via Raman scattering

The three-level Λ-type atom with degenerate atomic levels is considered, one of its transitions being driven by the coherent field, the other being coupled to the single-mode quantized field of the high-Q cavity. The probability of emission of a single photon in the cavity via Raman scattering versus the mutual orientation of polarization vectors of the cavity mode and of the driving coherent pulse is studied. The efficiency of the retrieval of a single-photon excitation, stored in the atomic ground state (as suggested, e.g., in paper [1]), versus the mutual orientation of polarizations of cavity modes and of the coherent ''write'' and ''read'' pulses is also investigated. The numerical calculations are carried out for the transitions between hyperfine components of the ground 6S1/2 and excited 6P3/2 states of Cesium atoms, which were exploited in the experiments [1]. The optimal polarizations providing the maximum probability of photon emission and maximum retrieval efficiency are determined