Precise Measurement of Magnetic Shielding Residual Field and Light Shift Based on ⁸⁷Rb Atomic Magnetometer

Atomic magnetometers (AMs) are used in various fields, including magnetocardiography (MCG) and magnetoencephalography (MEG). In AMs, accurately distinguishing and measuring the light-shift equivalent magnetic field generated by the pump beam from the remanent field within the central area of a magnetic shield have been a significant challenge. This article presents a novel measurement method that addresses this issue using 87Rb AMs. By exploiting the distinctive responses of the magnetometer to oscillating magnetic fields under different pump photon spin-polarization vectors s and employing a fitting technique at the resonance peak, we determined both the residual field and light shift. Furthermore, we conducted comprehensive numerical simulations to analyze the light shift of the pump beam under various conditions, e.g., photon spin vectors, intensities, and frequency detuning. In addition, experimental measurements were performed to investigate the pressure broadening effect on the D1 line of the cell. The proposed method allows precise measurement of remanent fields while eliminating the influence of light shift; thus, it is useful for high-precision atomic device measurements in diverse experimental settings.