Room temperature atomic frequency comb storage for light.

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 =4 hyperfine ground state of cesium. The frequency spacing of the classes is chosen to coincide with the =4-=5 hyperfine splitting of the 6 excited state, resulting in a broadband periodic absorbing structure consisting of two usually Doppler-broadened optical transitions. Weak coherent states of duration 2 are mapped into this atomic frequency comb with pre-programmed recall times of 8 and 12, 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.