High-Resolution Atomic Magnetometer-Based Imaging of Integrated Circuits and Batteries

Area of Science:

• Physics
• Magnetometry
• Sensor Technology

Background:

• Optically pumped magnetometers (OPMs) offer high sensitivity for magnetic field imaging.
• Achieving sub-millimeter spatial resolution at sub-picotesla sensitivities (< 1 pT/√Hz) is a significant challenge, especially in finite magnetic fields.

Purpose of the Study:

• To develop and demonstrate a high-resolution magnetic imaging system using a free-induction-decay (FID) OPM.
• To improve spatial resolution and sensitivity for non-invasive diagnostics of electronic circuits and batteries.

Main Methods:

• Integration of an FID OPM with a two-axis scanning micromirror for automated beam steering.
• Utilizing a double-pass optical configuration for optimal device positioning and reduced standoff distance (2.7 mm).
• Experimental validation using printed circuit boards (PCBs) and integrated circuits (ICs).

Main Results:

• Demonstrated sub-millimeter spatial resolution by imaging a PCB with 2 mm spaced copper tracks.
• Achieved an optimal field sensitivity of 0.5 pT/√Hz.
• Successfully resolved asymmetries in a bridge rectifier IC and tracked current dynamics in a ceramic battery.

Conclusions:

• The developed OPM system provides high-resolution magnetic field imaging with excellent sensitivity.
• The system shows significant potential for non-invasive diagnostics and in situ monitoring of electronic components and energy storage devices.