Near-unity indistinguishability of single photons emitted from dissimilar and independent atomic quantum nodes

Abstract

Generating indistinguishable photons from independent nodes is an important challenge for the development of quantum networks. In this work, we demonstrate the generation of highly indistinguishable single photons from two dissimilar atomic quantum nodes. One node is based on a fully blockaded cold Rydberg ensemble and generates on-demand single photons. The other node is a quantum repeater node based on a DLCZ quantum memory and emits heralded single photons after a controllable memory time that is used to synchronize the two sources. We demonstrate an indistinguishability of ${94.6 \pm 5.2 \%}$ for a temporal window including ${90\%}$ of the photons. This advancement opens new possibilities for interconnecting quantum repeater and processing nodes with high fidelity Bell-state measurement without sacrificing its efficiency.