Decoherence imaging of spin ensembles using a scanning single-electron spin in diamond

TL;DR

This paper demonstrates a method to image fluctuating magnetic fields from surface impurities using a scanning NV center in diamond, revealing spatial and temporal properties crucial for quantum sensing.

Contribution

It introduces an experimental approach to detect and image fluctuating magnetic fields via decoherence of a scanning NV center, advancing nanoscale magnetic imaging techniques.

Findings

Detected magnetic signals from surface impurities with high sensitivity.

Mapped spatial and temporal properties of surface paramagnetic impurities.

Provided insights for improving coherence in quantum sensing applications.

Abstract

The nitrogen-vacancy (NV) defect center in diamond has demonstrated great capability for nanoscale magnetic sensing and imaging for both static and periodically modulated target fields. However, it remains a challenge to detect and image randomly fluctuating magnetic fields. Recent theoretical and numerical works have outlined detection schemes that exploit changes in decoherence of the detector spin as a sensitive measure for fluctuating fields. Here we experimentally monitor the decoherence of a scanning NV center in order to image the fluctuating magnetic fields from paramagnetic impurities on an underlying diamond surface. We detect a signal corresponding to roughly 800 ${\mu}_B$ in 2 s of integration time, without any control on the target spins, and obtain magnetic-field spectral information using dynamical decoupling techniques. The extracted spatial and temporal properties of the surface paramagnetic impurities provide insight to prolonging the coherence of near-surface qubits for quantum information and metrology applications.