A Single-Beam Dual-Axis Atomic Spin Comagnetometer for Rotation Sensing

We describe a dual-axis atomic spin comagnetometer for rotation sensing using a single laser beam. A circularly polarized laser is used to pump the co-located atomic ensembles of alkali metal and noble gas and probe their gyroscopic precession at the same time, which is different from the traditional two-beam orthogonal pump-probe configuration. Combined with magnetic field modulations perpendicular to the laser propagating direction, the comagnetometer could measure dual-axis rotation rates simultaneously. This system is demonstrated theoretically and experimentally. A rotation sensitivity of 5.1 × 10–7 rad s−1 Hz−1∕2 and a bias instability of 0.016 °/h have been achieved. The theory and method presented here shed light on the way to miniaturize the comagnetometer with high precision for practical applications.