Portable Magnetometry for Detection of Biomagnetism in Ambient Environments

M. E. Limes, E. L. Foley, T. W. Kornack, S. Caliga, S. McBride, A. Braun, W. Lee, V. G. Lucivero, M. V. Romalis

Research output: Contribution to journalArticlepeer-review

118 Scopus citations


We present a method of optical magnetometry with parts-per-billion resolution that is able to detect biomagnetic signals generated from the human brain and heart in Earth's ambient environment. Our magnetically silent sensors measure the total magnetic field by detecting the free-precession frequency in a highly spin-polarized alkali-metal vapor. A first-order gradiometer is formed from two magnetometers that are separated by a 3-cm baseline. Our gradiometer operates from a laptop consuming 5 W over a USB port, enabled by state-of-the-art microfabricated alkali-vapor cells, advanced thermal insulation, custom electronics, and compact lasers within the sensor head. The gradiometer has a sensitivity of 16 fT/cm/Hz1/2 outdoors, which we use to detect neuronal electrical currents and magnetic cardiography signals. Recording of neuronal magnetic fields is one of a few available methods for noninvasive functional brain imaging that usually requires extensive magnetic shielding and other infrastructure. This work demonstrates the possibility of a dense array of portable biomagnetic sensors that are deployable in a variety of natural environments.

Original languageEnglish (US)
Article number011002
JournalPhysical Review Applied
Issue number1
StatePublished - Jul 2020

All Science Journal Classification (ASJC) codes

  • General Physics and Astronomy


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