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Publication - Professor John Rarity

    Magnetic-field-learning using a single electronic spin in diamond with one-photon-readout at room temperature

    Citation

    Santagati, R, Gentile, AA, Knauer, S, Schmitt, S, Paesani, S, Granade, C, Wiebe, N, Osterkamp, C, McGuinness, LP, Wang, J, Thompson, MG, Rarity, JG, Jelezko, F & Laing, A, 2018, ‘Magnetic-field-learning using a single electronic spin in diamond with one-photon-readout at room temperature’. Physical Review X, vol 9.

    Abstract

    Nitrogen-vacancy (NV) centres in diamond are appealing nano-scale quantum sensors for temperature, strain, electric fields and, most notably, for magnetic fields. However, the cryogenic temperatures required for low-noise single-shot readout that have enabled the most sensitive NV-magnetometry reported to date, are impractical for key applications, e.g. biological sensing. Overcoming the noisy readout at room-temperature has until now demanded repeated collection of fluorescent photons, which increases the time-cost of the procedure thus reducing its sensitivity. Here we show how machine learning can process the noisy readout of a single NV centre at room-temperature, requiring on average only one photon per algorithm step, to sense magnetic field strength with a precision comparable to those reported for cryogenic experiments. Analysing large data sets from NV centres in bulk diamond, we report absolute sensitivities of $60$ nT s$^{1/2}$ including initialisation, readout, and computational overheads. We show that dephasing times can be simultaneously estimated, and that time-dependent fields can be dynamically tracked at room temperature. Our results dramatically increase the practicality of early-term single spin sensors.

    Full details in the University publications repository