Quantum storage via refractive-index control

Off-resonant Raman interaction of a single-photon wave packet and a classical control field in an atomic medium with controlled refractive index is investigated. It is shown that a continuous change of refractive index during the interaction leads to the mapping of a single photon state to a superposition of atomic collective excitations (spin waves) with different wave vectors and vice versa. The suitability of refractive-index control for developing multichannel quantum memories is discussed and possible schemes of implementation are considered.