Sub-picotesla widely tunable atomic magnetometer operating at room-temperature in unshielded environments

TL;DR

This paper presents a room-temperature, unshielded atomic magnetometer with sub-picotesla sensitivity, broad tunability, and automatic magnetic field stabilization, suitable for diverse practical applications.

Contribution

The work introduces a highly sensitive, unshielded atomic magnetometer operating at room temperature with automatic stabilization and broad frequency tunability, advancing practical magnetic sensing.

Findings

Achieved 130 fT/√Hz sensitivity in unshielded environment

Demonstrated stable operation across kHz to MHz frequencies

Reduced 50 Hz noise by an order of magnitude

Abstract

We report on a single-channel rubidium radio-frequency atomic magnetometer operating in un-shielded environments and near room temperature with a measured sensitivity of 130 fT/\sqrt{Hz}. We demonstrate consistent, narrow-bandwidth operation across the kHz - MHz band, corresponding to three orders of magnitude of magnetic field amplitude. A compensation coil system controlled by a feedback loop actively and automatically stabilizes the magnetic field around the sensor. We measure a reduction of the 50 Hz noise contribution by an order of magnitude. The small effective sensor volume, 57 mm^3, increases the spatial resolution of the measurements. Low temperature operation, without any magnetic shielding, coupled with the broad tunability, and low beam power, dramatically extends the range of potential field applications for our device.