Free-space single-photon transistor based on Rydberg interaction

Abstract

An all-optical transistor working on the single-photon level is implemented using an ultracold atomic cloud as a medium. The interaction mechanism between gate and source photons is achieved by mapping these photons onto strongly interacting Rydberg excitations. Using a single gate photon more than 100 source photons can be switched. As an application of this transistor, we demonstrate nondestructive detection of a single Rydberg atom with a fidelity of 0.79.