Cavity enhanced spin-photon interaction for a diamond based quantum network

Fast and efficient entanglement generation is a fundamental building block for proposed long distance quantum networks. Nitrogen vacancy (NV) centers in diamond present a promising platform for such a network, because of their long electron spin coherence times, available nuclear spin registers and near lifetime limited optical properties. However, the small fraction of photons emitted into the zero phonon line has so far limited entanglement generation rates to below 39 Hz. We construct high finesse fiber based cavities with a microns thick diamond membrane and measure the NV cavity interaction. Purcell enhancement of the emission into the zero phonon line and better coupling efficiency could increase entangling rates by two orders of magnitude. Here we report on the latest results towards these goals.