In Situ Evaluation and Efficient Suppression of Magneto-Optical Misalignment in K–Rb–21Ne Comagnetometers

This study investigates the impact of magneto-optical misalignment on atomic spin responses in a spin-exchange relaxation-free (SERF) comagnetometer and proposes a method to measure and compensate for misalignment angles. By analyzing nuclear spin precession under varying bias magnetic field strengths, both the nuclear spin equivalent magnetic field ( $B_{n}$ ) and the misalignment angle $\theta $ between the pump beam and the main magnetic field are extracted. To suppress the identified misalignment, a novel alignment technique based on periodic strong magnetic field pulses is introduced. This method enables rapid in situ adjustment of the pump beam direction, thereby enhancing nuclear spin self-compensation and overall system performance. Experimental validation demonstrates that the proposed approach improves the suppression of transverse magnetic field interference, with a 43.2% enhancement in magnetic response attenuation. Additionally, magneto-optical alignment optimization results in marked improvements in system stability and sensitivity: the Allan deviation at 100 s is reduced by 34%, and the inertial measurement noise at 1 Hz decreases by 43.3%, achieving a sensitivity of $3.56\times {10^{ - 6}}{{\mathrm { }}^{\circ } }/\text {s}/\sqrt {\text {Hz}}$ .