Comparing continuous and pulsed nitrogen-vacancy DC magnetometry in the optical-power-limited regime

Abstract

Ensembles of nitrogen-vacancy (NV) center spins in diamond offer a robust, precise, and accurate magnetic sensor. As their applications move beyond the laboratory, practical considerations including size, complexity, and power consumption become important. Here, we compare two commonly employed NV magnetometry techniques—continuous-wave (CW) versus pulsed magnetic resonance—in a scenario limited by the total available optical power. We develop a consistent theoretical model for the magnetic sensitivity of each protocol that incorporates NV photophysics—in particular, including the incomplete spin polarization associated with limited optical power; after comparing the models’ behavior to experiments, we use them to predict the relative DC sensitivity of CW versus pulsed operation for an optical-power-limited, shot-noise-limited NV ensemble magnetometer. We find a ∼2−3× gain in sensitivity for pulsed operation, which is significantly smaller than seen in power-unlimited, single-NV experiments [Phys. Rev. B 84, 195204 (2011)PRBMDO0163-182910.1103/PhysRevB.84.195204]. Our results provide a resource for practical sensor development, informing protocol choice and identifying optimal operation regimes when optical power is constrained.