Background magnetic field automatically compensated atomic magnetometer for bio-magnetic field sensing

We described an atomic co-magnetometer which could effectively suppress the background fluctuating magnetic field as sensing the fast changing bio-magnetic field such as magnetic field from the brain. In the co-magnetometer, the hyper-polarized nuclear spin could produce a magnetic field which will shield the electron spin from the background fluctuation DC magnetic field. The nuclear spins like an automatic magnetic field shields and dynamically compensate the fluctuated background magnetic field. The magnetic field suppression effect is studied and we find that the suppression is closely related to several parameters such as the electron spin magnetic field, the nuclear spin magnetic field and the holding magnetic field. We show the magnetic field suppression ability of the magnetometer and magnetic field sensitivity is measured. Finally, we do a simulation for the magnetometer as it is utilized for detecting brain magnetic field under fluctuation background magnetic field.