Measurement and suppression of tensor light shift for nonlinear magneto-optical rotating atomic magnetometers

In the NMOR atomic magnetometer, the tensor light shift is identified as a critical systemic error that affects the accuracy of magnetic resonance frequency measurements. In this paper, we present a tensor light shift measurement and suppression method based on Linear Resonance Frequency Variation and Reverse Magnetic Compensation (LRFV-RMC), which utilizes the resonance frequency linear dependence on the light shift, along with a suppression technique based on reverse magnetic compensation. To further enhance the compensation accuracy and improve the long-term stability of magnetic field measurement, a closed-loop light power control scheme is introduced. The theoretical models of resonant frequency and tensor light shift are established and the mechanism of the influence of light shift on resonance frequency is clarified. Additionally, the light shift and its corresponding magnetic resonance signals are investigated theoretically and experimentally under different light power, polarization direction and magnetic field amplitude. As a result, compared to the existing system, the proposed method effectively compensates for tensor light shift and improves the long-term stability of the magnetic resonance signal by at least 25.8%. This work provides a practical approach to improving the accuracy and stability of NMOR atomic magnetometers.