Optically pumped atomic magnetometer and biomagnetic neuroimaging

Abstract

Optically pumped magnetometer (OPM) is a sensor based on electron-spin polarization of alkali-metal atoms. We have been developing super-sensitive compact OPMs as well as innovative biomagnetic neuroimaging systems. OPMs using alkali metal vapors contained in glass cells enable to measure extremely small magnetic fields. In recent years, OPMs have reached sensitivities comparable to and even surpassing those of superconducting quantum interference devices (SQUIDs). In addition, OPM has the intrinsic advantage of not requiring cryogenic cooling. After describing the principle of OPM, we introduce our recent results of MEG and NMR/MRI measurements to demonstrate its feasibility as a magnetic sensor towards innovative optical biomagnetic neuroimaging systems. Finally, we describe some future research directions of the OPM-based biomagnetic neuroimaging systems.