Simulation of Three-Dimensional Polarization Distribution in SERF Inertial Measurement Atomic Spin Ensembles Based on Light Field Manipulation

The inertial measurement system based on the SERF effect utilizes the rotation of the inertia-sensitive space with longitudinally hyperpolarized nuclear spin, possessing the potential for ultra-high sensitivity measurement, and has become an important development direction for the high-sensitivity miniaturized inertial navigation systems. The polarization distribution uniformity in the atomic spin ensemble significantly influences the scale factor error and bias stability of the SERF inertial measurement system. This paper analyses the factors affecting the longitudinal and transverse polarization distribution in the atomic spin coupled ensemble of the SERF inertial measurement system. To address the issue of non-uniform polarization rate distribution in the electron spin-nuclear spin coupled ensemble, a Bloch differential equation model is established. Using light field manipulation techniques, three-dimensional polarization rate distribution of the atomic spin ensemble under Gaussian, flat-top, and hollow beam pumping are simulated. Relevant simulation parameters are optimized, with over 80% of the normalized nuclear spin polarization rate considered as the uniform region. Under hollow beam pumping, the transverse nuclear spin polarization uniformity is improved by 88.3% compared to Gaussian beams and by 20.9% compared to flat-top beams, providing a theoretical basis for further enhancing the polarization uniformity in the atomic spin coupled ensemble.