Optically pumped atomic magnetometer: Toward novel MEG and MRI systems

Optically pumped atomic magnetometers (OPAMs) using alkali metal vapors contained in glass cells have reached sensitivities comparable to and even surpassing those of SQUIDs. In recent years, OPAMs operating under spin-exchange relaxation-free conditions have reached sensitivities the sub-femto tesla range. OPAMs have the intrinsic advantage of not requiring cryogenic cooling. Therefore, OPAMs are currently expected to overtake SQUIDs. After describing principles of the OPAM, we introduce recent results of biomagnetic field measurements such as MCG and MEG. Finally, we describe the feasibility of atomic magnetometers as magnetic sensors for measuring MEG and MRI signals simultaneously. © 2014, Japan Soc. of Med. Electronics and Biol. Engineering. All rights reserved.