Xing Bozheng, Sun Chang, Liu Ziao, Zhao Junpeng, Lu Jixi, Han Bangcheng, Ding Ming
Opt Express. 2021 Feb 15;29(4):5055-5067. doi: 10.1364/OE.416797.
In the spin-exchange relaxation-free (SERF) magnetometer, the probe noise is a consequential factor affecting the gradiometric measurement sensitivities. In this paper, we proposed a new characteristics model of the probe noise based on noise separation. Different from noise analysis on single noise source, we considered most of the noise sources influencing the probe system and realized noise sources level measurement experimentally. The results demonstrate that the major noise type changes with the signal frequency. Below 10 Hz, the probe noise mainly comes from the sources independent of light intensity such as the vibration, which accounts for more than 50%; while at 30 Hz, the photon shot noise and the magnetic noise are the main origins, with proportion about 43% and 32%, respectively. Moreover, the results indicate that the optimal probe light intensity with highest sensitivity appears when the response of the magnetic noise is equal to the sum of the electronic noise and half of the shot noise. The optimal intensity gets larger with higher signal frequency. The noise characteristics model could be applied in modulating or differential optical systems and helps sensitivity improvement in SERF magnetometer.
在自旋交换无弛豫（SERF）磁力计中，探头噪声是影响梯度测量灵敏度的一个重要因素。本文提出了一种基于噪声分离的探头噪声新特性模型。与对单个噪声源的噪声分析不同，我们考虑了影响探头系统的大多数噪声源，并通过实验实现了噪声源电平测量。结果表明，主要噪声类型随信号频率而变化。在10Hz以下，探头噪声主要来自与光强无关的源，如振动，其占比超过50%；而在30Hz时，光子散粒噪声和磁噪声是主要来源，分别占比约43%和32%。此外，结果表明，当磁噪声的响应等于电子噪声与散粒噪声的一半之和时，出现灵敏度最高的最佳探头光强。信号频率越高，最佳光强越大。该噪声特性模型可应用于调制或差分光学系统，并有助于提高SERF磁力计的灵敏度。
