All-optical single spin in silicon*

Silicon is an ideal platform for commercial quantum technologies: it unites advanced photonics and the microelectronics industry, as well as hosting record-setting long-lived spin qubits. We have been exploring a class of silicon emitters, the silicon colour centres, that are silicon analogues of the diamond color centres (NV, SiV, GeV). One such emitter, the T centre, was recently discovered to combine long-coherence electronic and nuclear spins with narrow, telecommunications-band optical transitions in isotopically purified silicon. In this talk I present the fabrication of commercial-grade silicon T centre devices and identify single centres with photonically enhanced emission. These emitters are orders of magnitude brighter than previous silicon spin-photon centres and have promising linewidths for useful quantum devices. The qubit states of a single T centre-bound spin are prepared and measured in  the first all-optical measurement of individual spins in silicon. Waveguide-coupled T centre devices producing spin-entangled photons could make immediate use of integrated silicon photonic networks boasting low-loss active components, efficient coupling to standard telecommunications fibres, and efficient photon detectors for a complete spin-photon network on chip.