An integrated diamond nanophotonics platform for quantum optical networks

We demonstrate a platform for quantum optical networks based on silicon-vacancy (SiV) and germanium-vacancy (GeV) color centers in diamond nanodevices. By placing SiV centers inside diamond photonic crystal cavities, we realize a quantum optical switch controlled by a single SiV. Raman transitions are used to realize a single-photon source with a tunable frequency and bandwidth in a diamond waveguide. We measure intensity correlations of indistinguishable Raman photons emitted into a single waveguide, observing a quantum interference effect resulting from the superradiant emission of two entangled SiV centers. We incorporate GeV centers into nanoscale waveguides and demonstrate high single atom-photon interaction probabilities in a single-pass. We discuss prospects for a high-cooperativity (C \textgreater 10) spin-photon interface using GeV centers in diamond nanocavities.