Sensitivity Thresholds in Inhomogeneous NV Ensemble Magnetometry

We report optimal spin subsets for solid-state ensemble quantum sensing [1]. By quantifying each spin sensor’s Fisher information for the collective metrology signal, we derive a sensitivity threshold that defines the spin subset optimizing the ensemble sensitivity. We apply this framework to quantum magnetometry with nitrogen-vacancy centers in diamond. Optimal subsets are implemented using structured illumination to selectively excite the contributing sensors, and we analyze the impact of residual non-uniformity in the excitation profile. Our approach extends the range of quantum sensing application to complex, heterogeneous sensing environments.

[1] S. I. Kang et al., “Sensitivity threshold defines the optimal spin subset for ensemble quantum sensing,” arXiv:2512.10549 (2025).