INTERFACING A SINGLE ATOM WITH SINGLE PHOTONS

Abstract

In this work we present the interfacing of a single atom with single photons. We trap a single 87Rb atom in a free-space optical dipole trap, where efficient atom-light coupling is achieved via strong focusing. Single photons are generated by heralding on one photon of a time-correlated photon pair generated via four-wave mixing (FWM) in a cloud of cold 87Rb atoms. The interfacing is demonstrated in two ways. First, we generate single photons from the single atom via spontaneous emission, and interfere them the FWM photons in a Hong-Ou-Mandel interference experiment. We observe a high visibility of 90±6%, demonstrating the compatibility between the single atom and FWM systems. Next, we send the FWM photons directly to the single atom and investigate the scattering dynamics for photons with exponentially rising and decaying temporal profiles. The two shapes give rise to different transient atomic excitation, but a similar overall extinction.