Optimizing Spin Readout of the Nitrogen-Vacancy Center in Diamond with Spin-to-Charge Conversion

The nitrogen-vacancy center in diamond is a mature platform for quantum technology, enabling sophisticated quantum information protocols as well as versatile quantum sensors operating in previously unreachable size and field regimes. The standard photoluminescence-based spin readout is fast (300 ns) but typical measurements yield only a few hundredths of a photon on average, necessitating tens of thousands of repeats to overcome shot noise in detecting the spin state. Spin-to-charge conversion (SCC) offers an alternative readout with significantly improved single-shot information. However, this benefit comes at the expense of orders of magnitude longer readout durations. Here, we present a framework for optimizing the SCC readout parameters that leads to dramatic reductions in overall measurement acquisition times [1]. The improvements arise from the combination of an analytical charge readout model with numerical optimization of the overhead durations. We discuss relevant applications such as T₁ relaxometry and control of nuclear registers and outline how other spin readout methods can benefit from this framework.
[1] D.A. Hopper et al. Micromachines 9, 437 (2018)