Interference in Atomic Magnetometry

TL;DR

This paper uncovers a previously unknown interference effect in atomic magnetometers that significantly impacts measurement accuracy, and proposes methods to detect, characterize, and mitigate this systematic issue in various scientific applications.

Contribution

The study identifies and characterizes a new interference effect in atomic magnetometers, providing a standard detection approach and demonstrating its impact on NMR and biomagnetic measurements.

Findings

Good agreement between predictions and experimental data in ultralow-field NMR spectra.

Interference effects can cause asymmetric resonant line amplitudes.

Accounting for interference improves measurement accuracy in applications.

Abstract

Atomic magnetometers are highly sensitive detectors of magnetic fields that monitor the evolution of the macroscopic magnetic moment of atomic vapors, and opening new applications in biological, physical, and chemical science. However, the performance of atomic magnetometers is often limited by hidden systematic effects that may cause misdiagnosis for a variety of applications, e.g., in NMR and in biomagnetism. In this work, we uncover a hitherto unexplained interference effect in atomic magnetometers, which causes an important systematic effect to greatly deteriorate the accuracy of measuring magnetic fields. We present a standard approach to detecting and characterizing the interference effect in, but not limited to, atomic magnetometers. As applications of our work, we consider the effect of the interference in NMR structural determination and locating the brain electrophysiological symptom, and show that it will help to improve the measurement accuracy by taking interference effects into account. Through our experiments, we indeed find good agreement between our prediction and the asymmetric amplitudes of resonant lines in ultralow-field NMR spectra -- an effect that has not been understood so far. We anticipate that our work will stimulate interesting new researches for magnetic interference phenomena in a wide range of magnetometers and their applications.