Spatial symmetry-broken atomic magnetometry

We report an atomic magnetic sensor that leverages the spatial symmetry-broken (SSB) properties of the four-wave mixing (FWM) process induced by an external weak magnetic field. The dispersive signals around the center of zero magnetic field are obtained from counterpropagating polarization-selective FWM signals in a rubidium vapor cell. The SSB magnetometer has a linear response within -5 <i>μ</i>T to 5 <i>μ</i>T, and the magnetic sensitivity is about 10 pT/Hz at 10 Hz, and the bandwidth is in the range of 18.25 kHz. This method would open diverse applications ranging from biomagnetic sensing to Earth's magnetic field mapping as a robust atomic magnetic sensor.