https://doi.org/10.1140/epjqt/s40507-025-00400-y
Research
Towards a multi-channel zero-field optically pumped magnetometer for imaging
1
Fraunhofer Institute for Physical Measurement Techniques IPM, Georges-Köhler-Allee 301, 79110, Freiburg im Breisgau, Germany
2
University of Freiburg, IMTEK, Georges-Köhler-Allee 102, 79110, Freiburg im Breisgau, Germany
3
Paul M. Rady Department of Mechanical Engineering, University of Colorado, 80309, Boulder, CO, USA
4
FieldLine Inc., 80301, Boulder, CO, USA
a
ronja.rasser@ipm.fraunhofer.de
Received:
14
April
2025
Accepted:
28
July
2025
Published online:
13
August
2025
We present a design for a multi-channel optically pumped zero-field magnetometer utilizing a 200-μm-thick Rubidium vapor cell. The vapor cell and its housing are designed to reduce the minimal distance between a magnetic sample and the sensing volume to about 1 mm, to optimize the effective spatial resolution. The thin vapor cell, filled with 2 atm of nitrogen as a buffer gas reduces the volume across which the magnetic field is averaged. The vapor cell is fully illuminated by a single laser beam, and the transmitted light is imaged onto a 4 x 4 photodiode array, allowing for simultaneous measurement of a magnetic field distribution with up to 16 channels. The performance of the magnetometer is studied for all channels. It is shown that the sensor can operate in the spin-exchange relaxation-free regime with a projected photon-shot noise limited noise floor of about 1 pT/Hz1/2 for a sensitive voxel size of approximately 600 μm x 600 μm x 200 μm.
Key words: Spin-exchange relaxation free / Optically pumped magnetometer / Imaging magnetic fields / Multi-pixel optically pumped magnetometer / Imaging optically pumped magnetometer / Magnetic field measurement
© The Author(s) 2025
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