Improved quantum sensing with a single solid-state spin via spin-to-charge conversion

Monitoring the coherent evolution of a quantum system due to controlled interaction with its environment allows the probing of those surroundings. Such a quantum sensor can be improved by prolonging its coherence time, or using better state-readout techniques. This study shows how the choice of spin-readout technique impacts the performance of a single N-$V$ center in diamond. In particular, a technique based on spin-to-charge conversion significantly improves both readout noise per shot and sensitivity in ac magnetometry. The authors also identify applications where single-shot spin-readout noise, not sensitivity, is the limiting factor, such as some types of biomagnetometry.