



01697nas a2200205   4500008004100000245010900041210006900150260001300219520100800232100003001240700002801270700003101298700002401329700001601353700001601369700002501385700002301410700002101433856003701454       2020                        eng d00aOn-demand indistinguishable single photons from an efficient and pure source based on a Rydberg ensemble0 aOndemand indistinguishable single photons from an efficient and   c3/4/20203 a<p>Single photons coupled to atomic systems have shown to be a promising platform for developing quantum technologies. Yet a bright on-demand, highly pure and highly indistinguishable single-photon source compatible with atomic platforms is lacking. In this work, we demonstrate such a source based on a strongly interacting Rydberg system. The large optical nonlinearities in a blockaded Rydberg ensemble convert coherent light into a single-collective excitation that can be coherently retrieved as a quantum field. We observe a single-transverse-mode efficiency up to 0.18(2), g(2)=2.0(1.5)&times;10&minus;4, and indistinguishability of 0.982(7), making this system promising for scalable quantum information applications. Accounting for losses, we infer a generation probability up to 0.40(4). Furthermore, we investigate the effects of contaminant Rydberg excitations on the source efficiency. Finally, we introduce metrics to benchmark the performance of on-demand single-photon sources.&nbsp;</p>1 aOrnelas-Huerta, Dalia, P.1 aCraddock, Alexander, N.1 aGoldschmidt, Elizabeth, A.1 aHachtel, Andrew, J.1 aWang, Yidan1 aBienias, P.1 aGorshkov, Alexey, V.1 aRolston, Steve, L.1 aPorto, James, V.  uhttps://arxiv.org/abs/2003.02202