arXiv:2011.03765 · Optics Letters
Room temperature atomic frequency comb storage for light
D. Main, T. M. Hird, Shaobo Gao, Ian A. Walmsley, Patrick M. Ledingham
Abstract
We demonstrate coherent storage and retrieval of pulsed light using the atomic frequency comb protocol in a room temperature alkali vapor. We utilize velocity-selective optical pumping to prepare multiple velocity classes in the F = 4 hyperfine ground state of cesium. The frequency spacing of the classes is chosen to coincide with the F ′ = 4 − F ′ = 5 hyperfine splitting of the 6 2 P 3 / 2 excited state, resulting in a broadband periodic absorbing structure consisting of two usually Doppler-broadened optical transitions. Weak coherent states of duration 2 n s are mapped into this atomic frequency comb with pre-programmed recall times of 8 n s and 12 n s , with multi-temporal mode storage and recall demonstrated. Utilizing two transitions in the comb leads to an additional interference effect upon rephasing that enhances the recall efficiency.