Noise characterization of an atomic magnetometer at sub-millihertz frequencies

TL;DR

This study measures and analyzes the low-frequency noise of an all-optical atomic magnetometer to evaluate its suitability for space missions like LISA, identifying key noise sources and potential for improvement.

Contribution

It provides a detailed noise characterization of an atomic magnetometer at sub-millihertz frequencies, assessing its potential for space-based low-frequency magnetic field measurements.

Findings

Suitable sensitivity for LISA requirements

Identification of dominant low-frequency noise sources

Need for further miniaturization and noise reduction

Abstract

Noise measurements have been carried out in the LISA bandwidth (0.1 mHz to 100 mHz) to characterize an all-optical atomic magnetometer based on nonlinear magneto-optical rotation. This was done in order to assess if the technology can be used for space missions with demanding low-frequency requirements like the LISA concept. Magnetometry for low-frequency applications is usually limited by $1/f$ noise and thermal drifts, which become the dominant contributions at sub-millihertz frequencies. Magnetic field measurements with atomic magnetometers are not immune to low-frequency fluctuations and significant excess noise may arise due to external elements, such as temperature fluctuations or intrinsic noise in the electronics. In addition, low-frequency drifts in the applied magnetic field have been identified in order to distinguish their noise contribution from that of the sensor. We have found the technology suitable for LISA in terms of sensitivity, although further work must be done to characterize the low-frequency noise in a miniaturized setup suitable for space missions.