Wang Mengke, Kong Jia, Fu Jiqing, Liu Hao, Lu Xiao-Ming
Department of Physics, Hangzhou Dianzi University, Hangzhou 310018, China.
Magnetic Quality Laboratory, National Institute of Metrology, 100029 Beijing, China.
Rev Sci Instrum. 2022 May 1;93(5):053001. doi: 10.1063/5.0083923.
The performance of laser-based instruments heavily depends on the stability of their laser source. Some instruments, such as the Cs-He magnetometer, even require the frequency stabilization and the power stabilization at the same time. In this work, we design a double-locking system with a fiber-coupled output on a small bread board and apply it to the pump laser of a Cs-He magnetometer. By carefully choosing the stabilization methods, we significantly improve the long-term simultaneous stability of frequency and power of the pump laser. The laser frequency drifts in 2 h are reduced from 100 to 10 MHz. For 10 h continuous measurements, their Allan deviation obtains about two orders of magnitude improvement for the averaging time larger than 200 s and reaches σ(τ) = 1.57 × 10 with a 200 s averaging time. The laser power stability for 1.8 h also obtains two orders of magnitude improvement from 3.22% to 0.031%, and its power noise reaches a level that is very close to the electronic noise of the detector. Applying this stabilization system to the pump laser of a fiber-coupled Cs-He magnetometer, its magnetic sensor noise is significantly reduced from 0.158 to 0.009 nT, which is a reasonable noise for magnetic field detection. With this on-board design of the laser stabilization system, it is more convenient to transform the magnetometer into an outdoor device.
基于激光的仪器的性能在很大程度上取决于其激光源的稳定性。一些仪器，如铯氦磁力仪，甚至需要同时进行频率稳定和功率稳定。在这项工作中，我们在一个小实验板上设计了一个具有光纤耦合输出的双锁定系统，并将其应用于铯氦磁力仪的泵浦激光器。通过仔细选择稳定方法，我们显著提高了泵浦激光器频率和功率的长期同时稳定性。激光频率在2小时内的漂移从100兆赫兹降低到10兆赫兹。对于10小时的连续测量，当平均时间大于200秒时，其阿伦偏差提高了约两个数量级，在200秒平均时间下达到σ(τ)=1.57×10。激光功率在1.8小时内的稳定性也从3.22%提高到0.031%，提高了两个数量级，其功率噪声达到了非常接近探测器电子噪声的水平。将这种稳定系统应用于光纤耦合铯氦磁力仪的泵浦激光器，其磁传感器噪声从0.158纳特斯拉显著降低到0.009纳特斯拉，这对于磁场检测来说是一个合理的噪声。通过这种激光稳定系统的板载设计，将磁力仪转变为户外设备更加方便。
