Pang Haoying, Liu Feng, Fan Wenfeng, Wu Zhihong, Yuan Qi, Quan Wei
Opt Express. 2023 Feb 13;31(4):5215-5228. doi: 10.1364/OE.478875.
The magnetic field gradient affects the improvement of sensitivity and magnetic field suppression ability of the spin-exchange relaxation-free co-magnetometer. This paper proposes a response model of a co-magnetometer considering magnetic field gradient based on state-space method. The effects of transverse and longitudinal magnetic field gradients on the system's scale factor, bandwidth and magnetic field response are analyzed. The analysis shows that transverse gradient affects the whole frequency band of system response, including steady-state and dynamic performance, while longitudinal gradient only affects steady-state response. With the increase of the gradient, the effect becomes more significant. The test results are in agreement with the theory, proving the accuracy of the theoretical analysis. The rotational sensitivity at 1 Hz decreases from 6.51 ×10 °/s/Hz to 5.05×10 °/s/Hz in the presence of a magnetic field gradient of -40 nT/cm, so the effect of the magnetic field gradient is critical. This work provides an accurate model for evaluating the effects of magnetic field gradients and provides a method for suppressing gradients using gradient coils, which are important for improving the sensitivity and accuracy of co-magnetometers.
磁场梯度影响无自旋交换弛豫共磁力仪的灵敏度提升和磁场抑制能力。本文基于状态空间法提出了一种考虑磁场梯度的共磁力仪响应模型。分析了横向和纵向磁场梯度对系统比例因子、带宽和磁场响应的影响。分析表明，横向梯度影响系统响应的整个频段，包括稳态和动态性能，而纵向梯度仅影响稳态响应。随着梯度的增加，影响变得更加显著。测试结果与理论一致，证明了理论分析的准确性。在存在-40 nT/cm的磁场梯度时，1 Hz处的旋转灵敏度从6.51×10°/s/Hz降至5.05×10°/s/Hz，因此磁场梯度的影响至关重要。这项工作为评估磁场梯度的影响提供了一个精确模型，并提供了一种使用梯度线圈抑制梯度的方法，这对于提高共磁力仪的灵敏度和精度很重要。
