Synchronous Measurement of Magnetic Field and Rotation Using Longitudinal Magnetic Field Modulation in Atomic Spin Comagnetometers

Quantum sensors, renowned for their ultrahigh measurement sensitivity, have emerged as a promising technology for precision measurements in fields such as inertia and magnetic fields, attracting significant research interest in recent years. However, atomic spin comagnetometers operating in the spin-exchange relaxation-free (SERF) regime are susceptible to low-frequency noise, with the inherent coupling between magnetic field and inertial rotation signals severely limiting measurement stability. To address this issue, this study investigates the signal generation and decoupling mechanisms and proposes a dual-parameter synchronous measurement method based on longitudinal magnetic field modulation. Theoretical and experimental analyses reveal that the first-harmonic component exhibits a self-compensation effect (SCE) similar to the DC signal, enabling the construction of a dual-input–dual-output decoupling system. The proposed scheme is experimentally validated on a K–Rb–²¹Ne SERF comagnetometer platform, achieving simultaneous measurement of magnetic field and rotation under steady-state conditions, with a magnetic sensitivity of 2.03 pT/(Hz)^1/2 and an inertial rotation measurement sensitivity of 2.41