Trapping a Free-Propagating Single Photon in an Atomic Ensemble

Photons can be trapped into an atomic ensemble while maintaining its photonic part, resulting a strong confinement of photons in the ensemble. It leads potential applications about strong photon-photon interactions without a strong coupling between light and atoms based on cavity [1]. Recently, the observation for single stationary dark-state polariton has been reported [2], yet the trapping of single photon into the ensemble has not been reported so far. Here, we present the first experimental demonstration for the trapping of free-propagating single photon into an atomic ensemble.