Heading-error-free optical atomic magnetometry in the Earth-field range

TL;DR

This paper presents a new $^{87}$Rb optical atomic magnetometer that effectively eliminates heading errors caused by nonlinear Zeeman effects, enabling accurate geomagnetic measurements with high sensitivity at room temperature.

Contribution

The authors develop an alignment-based $^{87}$Rb magnetometer with a single resonance peak, reducing heading errors and suitable for practical geomagnetic applications.

Findings

Insensitive to NLZ-related heading errors

Photon-shot-noise-limited sensitivity of 9 fT/√Hz

Operates effectively in Earth's magnetic field environment

Abstract

Alkali-metal atomic magnetometry is widely used due to its high sensitivity and cryogen-free operation. However, when operating in geomagnetic field, it suffers from heading errors originating from nonlinear Zeeman (NLZ) splittings and magnetic resonance asymmetries, which lead to difficulties in mobile-platform measurements. We demonstrate an alignment based $^{87}$Rb magnetometer, which, with only a single magnetic resonance peak and well-separated hyperfine transition frequencies, is insensitive or even immune to NLZ-related heading errors. It is shown that the magnetometer can be implemented for practical measurements in the geomagnetic environments and the photon-shot-noise-limited sensitivity reaches $9\,{\rm{fT}}/\sqrt{\rm{Hz}}$ at room temperature.