The single-beam miniaturized atomic magnetometer with modulated magnetic field is one of the most capable approaches to biomagnetic measurements. The transmission intensity of the pumping beam is critical to the sensitivity of the magnetometer, which is affected by the density of alkali metal and the polarization of atomic spin. In this study, we investigated into the influence of three variables: the temperature of atomic vapour; the amplitude of the modulated magnetic field; the frequency of modulated magnetic field on the transmission intensity of pumping beam. We have defined their relationship into a function, and the calculated values through theoretical analysis have a high degree of fit with the measured values of numerous experiments. It is discovered that the transmission intensity decreases with the increase in temperature, and this effect is modified by the modulation index. A compact magnetometer is developed as a proof of concept based on single-beam scheme. The volume of this magnetometer is 10 cm³, and its dual axis sensitivity are both 30 fT/Hz. Based on this relationship we find that two major improvements are achieved by separating the DC and AC components of transmission intensity: 1. Realizing closed-loop temperature control for atomic vapour which improved the stability of the magnetometer. 2. Achieving closed-loop dual axis magnetic measurements under a single-beam scheme, which extends the magnetometer’s scope of application.

具有调制磁场的单光束微型原子磁力计是最有效的生物磁测量方法之一。泵浦光束的透射强度对磁力计的灵敏度至关重要，它受碱金属密度和原子自旋极化的影响。在这项研究中，我们研究了三个变量的影响：原子蒸气的温度；调制磁场的幅度；调制磁场频率对泵浦光束传输强度的影响。我们将它们的关系定义为一个函数，通过理论分析计算出的值与大量实验的实测值具有很高的拟合度。发现透射强度随着温度的升高而降低，这个效果是由调制指数修改的。作为基于单波束方案的概念验证，开发了一种紧凑型磁力计。这个磁力计的体积是 10 厘米³、双轴灵敏度均为30 fT/Hz 。基于这种关系，我们发现通过分离传输强度的直流和交流分量实现了两个主要改进： 1.实现了原子蒸气的闭环温度控制，提高了磁力计的稳定性。2、在单波束方案下实现闭环双轴磁测量，扩展了磁力计的应用范围。