Towards an efficient spin-photon interface with near-deterministically engineered defects in diamond

In this work, we demonstrate two developments, in device and material engineering respectively, towards an efficient spin-photon device using colour centres in diamond for scalable quantum computing networks: firstly, we report the emission enhancement of the coherent zero-phonon-line transistion of an nitrogen vacancy centre in a diamond membrane on coupling to a tunable open-cavity; secondly, we present a new method for deterministic writing of NV arrays in bulk diamond with a 96% yield of single defects, a 50 nm positional accuracy in the image plane, and NV electron spin coherence (T2) times of up to 170 microseconds.