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

Abstract

We report on a single-channel rubidium radio-frequency atomic magnetometer operating in unshielded environments and near room temperature with a measured sensitivity of 130 fT/ . We demonstrate consistent, narrow-bandwidth operation across the kHz-MHz band, corresponding to three orders of magnitude of the 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 in the 50 Hz noise contribution by an order of magnitude. The small effective sensor volume, 57 mm, 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.

Inductive Imaging of the Concealed Defects with Radio-Frequency Atomic Magnetometers

“…In particular, it enables operation at low frequencies, where the change in the penetration depth of the rf field is most significant. This category of sensors includes giant magnetoresistance (GMR) magnetometers [12][13][14], superconducting quantum interference devices (SQUIDs) [15,16] and atomic magnetometers [17][18][19][20][21][22][23][24][25][26].…”

A feed-forward measurement scheme for periodic noise suppression in atomic magnetometry

“…Schemes have been implemented which modify the ambient field around the experiment in order to reduce magnetic noise 18 . Often an additional sensor such as a fluxgate is used to generate an error signal 19 . Within active compensation there are two broad categories; feedback and feed-forward.…”

Electromagnetic induction imaging with atomic magnetometers: Unlocking the low-conductivity regime

“…Its output is used as the error signal of a feedback loop. 13,22 The magnetic field compensation system has a response band between DC and 1 kHz, imposed by the fluxgate.…”