Functional Neuroimaging with Multichannel Atomic Magnetometers

A key challenge in neuroscience is understanding human brain function and behavior at different scales. One powerful modality of functional neuroimaging is magnetoencephalography (MEG) that sensitively measures the magnetic fields produced by neuronal spike electrical activity. The leading high-sensitivity MEG systems are based on arrays of a low-temperature superconducting quantum interference device (SQUID) magnetometer, which presents multiple technological challenges mainly due to cryogenic operation and high cost. Further, these systems typically measure only cm-scale neuronal activity due to the trade-off between sensitivity and resolution. To overcome these limitations of the current MEG technology, we develop new approaches based on a cryogen-free multichannel atomic magnetometer (AM) that utilizes a single rubidium vapor cell, two broad laser beams, and a two-dimensional photodiode array. These approaches have a potential to reduce cost and fabrication effort. Especially, to realize micro-neuroimaging, the multichannel AM is integrated with an array of high-permeability flux guides, which serve to transmit the magnetic flux from a microscopic source of magnetic field to the cm-size AM to improve the resolution. In this talk, we will describe our approaches and present some progress.