Quantum memory for light via stimulated off-resonant Raman process: beyond the three-level Lambda-scheme approximation

TL;DR

This paper investigates a quantum memory scheme using stimulated off-resonant Raman processes in alkali atoms, revealing deviations from traditional models and demonstrating potential efficiency improvements by considering hyperfine states.

Contribution

It extends the three-level Lambda-scheme approximation by including hyperfine states, showing enhanced memory efficiency through detailed resonance analysis.

Findings

Deviations from three-level Lambda-scheme predictions when hyperfine states are included.

Enhanced memory efficiency at specific control field detunings.

Calculated Autler-Townes resonance structure for alkali atom media.

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 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 D1 optical transition, we show important deviations from the predictions of the usual three-level 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.