核磁共振陀螺仪泵浦光频率波动抑制

核磁共振陀螺仪利用原子核自旋磁矩在静磁场中进动频率的不变性敏感载体转动信息。针对泵浦激光频率漂移影响核磁共振陀螺仪性能的问题,研究了泵浦激光频率漂移影响核磁共振陀螺仪性能机理和抑制方法。通过分析核磁共振陀螺仪理论输出的数学模型和自旋光泵极化~(129)Xe核子的过程,阐明了泵浦激光频率波动对陀螺仪性能影响的机理。分析表明,为了获得更高的碱金属极化率和稳定性,从而得到更好的陀螺仪零偏稳定性,需要将泵浦光的频率稳定在~(87)Rb的原子的共振跃迁频率处。采用波长调制法实现了泵浦光频率的稳定控制。通过实验对比发现:稳频使得陀螺仪的零偏稳定性从389.68(°)/h(1σ)降低至40.74(°)/h(1σ),降低了89.5%。因而得出结论:抑制泵浦激光频率的漂移可以有效提高核磁共振陀螺仪的性能,主要体现在陀螺仪的零偏稳定性上。

Suppression of pump laser frequency drift of nuclear magnetic resonance gyroscope

The stable precession of the atomic spin along a static magnetic field is used to sense the system angular rate,which is the theoretical basis of Nuclear Magnetic Resonance Gyroscope (NMRG).In order to solve the problem that the performance of NMRG is influenced by the frequency fluctuation of pump laser,the influence mechanism and the way to control the fluctuation are studied.The theoretical model of NMRG is introduced,and the process of 129Xe polarization via Spin-Exchange Optical Pumping (SEOP) is analyzed.The analysis shows that the pump laser frequency needs to be stabilized to the resonance transition frequency of alkali atoms to get high and stable alkali atomic spin polarization and low bias-drift of NMRG.The wavelength modulation is adopted to realize the stable control of the frequency fluctuation of pump laser.The contrastive experiments show that the bias drift of NMRG is reduced to 40.74(°)/h (lσ) from 389.68(°)/h (lσ) after the pump laser frequency is controlled,which is reduced by 89.55％.It can be concluded that the control of fluctuation of pump laser can effectively improve the performance of NMRG,especially the bias stability.