Stray Magnetic Field Compensation with a Scalar Atomic Magnetometer

TL;DR

This paper presents a scalar atomic magnetometer system that actively compensates for stray magnetic fields, enhancing the detection of weak magnetic signals in low-field environments.

Contribution

The work introduces a dual channel scalar magnetometer with a phase-locked-loop control for effective stray field compensation, improving low-field magnetic detection.

Findings

Significantly improved detection of proton free induction decay signals.

Demonstrated effective compensation of time-dependent stray magnetic fields.

System performance and limitations analyzed and discussed.

Abstract

We describe a system for the compensation of time-dependent stray magnetic fields using a dual channel scalar magnetometer based on non-linear Faraday rotation in synchronously optically pumped Cs vapour. We detail the active control strategy, with an emphasis on the electronic circuitry, based on a simple phase-locked-loop integrated circuit. The performance and limits of the system developed are tested and discussed. The system was applied to significantly improve the detection of free induction decay signals from protons of remotely magnetized water precessing in an ultra-low magnetic field.