Dual-channel lock-in magnetometer with a single spin in diamond

TL;DR

This paper introduces a novel dual-channel lock-in magnetometry technique using a single NV center in diamond, enabling precise, wide-range, phase-sensitive magnetic field measurements with high sensitivity.

Contribution

It combines multi-pulse quantum sensing sequences with phase estimation algorithms for linearized, high-sensitivity magnetic field readout using a single spin.

Findings

Achieved nearly decoherence-limited sensitivity

Successfully reconstructed amplitude and phase of magnetic fields

Demonstrated measurement of random phase jumps and phase-sensitive frequency readout

Abstract

We present an experimental method to perform dual-channel lock-in magnetometry of time-dependent magnetic fields using a single spin associated with a nitrogen-vacancy (NV) color center in diamond. We incorporate multi-pulse quantum sensing sequences with phase estimation algorithms to achieve linearized field readout and constant, nearly decoherence-limited sensitivity over a wide dynamic range. Furthermore, we demonstrate unambiguous reconstruction of the amplitude and phase of the magnetic field. We show that our technique can be applied to measure random phase jumps in the magnetic field, as well as phase-sensitive readout of the frequency.