Dual-Mode Dead-Zone-Free Double-Resonance Alignment-Based Magnetometer

Magneto-optical double-resonance magnetometers are attractive candidates for sensitive measurements of magnetic fields but suffer from a fundamental problem known as the "dead zone": certain magnetic field directions where the magnetometer loses its sensitivity. We present a dead-zone-free double-resonance magnetometer with a single linearly polarized laser, which keeps uniform signal amplitude and isotropic sensitivity among varying magnetic field directions. The isotropic magnetometer can be switched between two modes, i.e., Mz mode insensitive to phase shifts and Mx mode with a higher upper bound of bandwidth. The dead-zone-free magnetometer exhibits a magnetic field noise floor of 0.9pT/Hz and 1.2pT/Hz in Mz and Mx modes, respectively. The proposed double-resonance magnetometer, benefiting from its compact single-beam structure, isotropic sensitivity, and capability of dual modes, would be useful for high-sensitivity magnetic field measurements in mobile applications.