Magnetic field sensitivity and decoherence spectroscopy of an ensemble of narrow-linewidth nitrogen-vacancy centers close to a diamond surface

TL;DR

This study demonstrates high-sensitivity magnetic field detection and decoherence spectroscopy using near-surface NV centers with narrow linewidths, enabling advanced magnetic imaging and impurity analysis.

Contribution

It introduces a method combining pulsed ESR and dynamic nuclear polarization to achieve shot-noise-limited sensitivity and characterizes decoherence mechanisms in NV ensembles.

Findings

Photon-shot-noise-limited sensitivity of 35 nT/Hz^{0.5} achieved.

Decoherence dominated by instantaneous diffusion, revealing impurity spin density.

Potential for enhanced two-dimensional magnetic imaging applications.

Abstract

We perform pulsed optically detected electron spin resonance to measure the DC magnetic field sensitivity and electronic spin coherence time T_2 of an ensemble of near-surface, high-density nitrogen-vacancy (NV) centers engineered to have a narrow magnetic resonance linewidth. Combining pulsed spectroscopy with dynamic nuclear polarization, we obtain the photon-shot-noise-limited DC magnetic sensitivity of 35 nT Hz^{-0.5}. We find that T_2 is controlled by instantaneous diffusion, enabling decoherence spectroscopy on residual nitrogen impurity spins in the diamond lattice and a quantitative determination of their density. The demonstrated high DC magnetic sensitivity and decoherence spectroscopy are expected to broaden the application range for two-dimensional magnetic imaging.