Entanglement between a trapped-ion qubit and a 780-nm photon via quantum frequency conversion

Future quantum networks will require the ability to produce matter-photon entanglement at photon frequencies not naturally emitted from matter qubit. This allows for a hybrid network architecture, where these photons can couple other tools and technologies useful tasks such as multiplexing, routing, storage, but which operate wavelengths different that of qubit source, while also reducing losses. Here, we demonstrate between trapped ion 780-nm photon, wavelength interact with neutral-Rb-based networking devices. A single barium is used 493-nm photons, entangled ion, are then frequency converted 780 nm preserving entanglement. We generate ion-photon fidelities $\ensuremath{\ge}0.93$(2) $\ensuremath{\ge}0.84$(2) respectively fidelity drop arising predominantly reduction in signal-noise our detectors compared 493 nm.