Optimization of Temperature Sensitivity Using the Optically Detected Magnetic-Resonance Spectrum of a Nitrogen-Vacancy Center Ensemble

Temperature sensing with N-$V$ centers using quantum techniques is very promising, and the fundamental limit of sensitivity with a high-density ensemble has not yet been revealed. The authors estimate how several noise parameters depend on the spin concentration in such a system, and use those estimates to predict the optimal concentration of centers for maximizing temperature sensitivity. The sensitivity limit identified here is much better than in previous reports, indicating the excellent potential of temperature sensing with N-$V$ centers.