High-resolution atomic magnetometer-based imaging of integrated circuits and batteries

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Hunter, Dominic and Mrozowski, Marcin S. and Ingleby, Stuart J. and Read, Timothy S. and McWilliam, Allan P. and McGilligan, James P. and Bauer, Ralf and Schwindt, Peter D. D. and Griffin, Paul F. and Riis, Erling (2026) High-resolution atomic magnetometer-based imaging of integrated circuits and batteries. IEEE Transactions on Instrumentation and Measurement. ISSN 0018-9456 (https://doi.org/10.1109/tim.2026.3664381)

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Abstract

Optically pumped magnetometers (OPMs) have emerged as a powerful technique for high-resolution magnetic field imaging. However, achieving sub-millimeter spatial resolution at sub-picotesla sensitivities (< 1 pT/ √ Hz) remains challenging, particularly under finite-field conditions. We present a high-resolution magnetic imaging system based on a free-induction-decay (FID) OPM integrated with a two-axis scanning micromirror for automated beam steering. The double-pass optical configuration allows millimeter-scale devices under test (DUTs) to be positioned directly behind the vapor cell. This enables a standoff distance of 2.7 mm between the magnetic source and the atomic vapor, improving practical imaging resolution by increasing the amplitude of near-field magnetic signals sampled within the sensitive volume. Spatial resolution is experimentally demonstrated by imaging a custom printed circuit board (PCB) containing antiparallel copper tracks spaced 2 mm apart, with measured field maps in close agreement with Biot–Savart predictions. The OPM achieves an optimal field sensitivity of 0.5 pT/ √ Hz, demonstrating the system’s capability for high-precision magnetic field measurements. The imaging system is further validated by resolving polarity-dependent asymmetries in a bridge rectifier integrated circuit (IC) and tracking current dynamics in a ceramic battery in situ. These results highlight the potential of OPM-based systems for noninvasive diagnostics of electronic circuits and batteries.

ORCID iDs

Hunter, Dominic ORCID logoORCID: https://orcid.org/0000-0003-4177-6027, Mrozowski, Marcin S. ORCID logoORCID: https://orcid.org/0000-0001-9616-4058, Ingleby, Stuart J. ORCID logoORCID: https://orcid.org/0000-0001-7473-9949, Read, Timothy S., McWilliam, Allan P. ORCID logoORCID: https://orcid.org/0009-0002-9004-8368, McGilligan, James P. ORCID logoORCID: https://orcid.org/0000-0002-6514-9696, Bauer, Ralf ORCID logoORCID: https://orcid.org/0000-0001-7927-9435, Schwindt, Peter D. D., Griffin, Paul F. ORCID logoORCID: https://orcid.org/0000-0002-0134-7554 and Riis, Erling ORCID logoORCID: https://orcid.org/0000-0002-3225-5302;
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