arXiv:1007.3391 · Physical Review A
Quantum memory for light via a stimulated off-resonant Raman process: Beyond the three-level Λ -scheme approximation
A. S. Sheremet, L. V. Gerasimov, Igor M. Sokolov, Dmitriy V. Kupriyanov, O. S. Mishina, E. Giacobino, Julien Laurat
Abstract
We consider a quantum memory scheme based on the conversion of a signal pulse into a long-lived spin coherence via stimulated off-resonant Raman process. For a storing medium consisting of alkali-metal atoms, we have calculated the Autler-Townes resonance structure created by a strong control field. By taking into account the upper hyperfine states of the ${D}_{1}$ optical transition, we show important deviations from the predictions of the usual three-level $\ensuremath{\Lambda}$-scheme approximation and we demonstrate an enhancement of the process for particular detunings of the control. We estimate the memory efficiency one can obtain using this configuration.