锶原子光钟闭环控制系统的设计与实现

为了实现~(87)Sr原子光钟的闭环运行,根据将超稳激光频率锁定在钟跃迁超精细能级自旋极化谱双峰中间的锁频原理,设计和实现了锶原子光钟闭环控制系统。首先,详细分析了~(87)Sr原子光钟闭环运行的具体需求,包括冷原子制备及钟跃迁探测、闭环锁定等阶段中所需要的控制信号及其时序;然后,根据该需求设计了时序控制和频率控制的物理系统;最后,利用LabVIEW虚拟仪器开发平台和NI硬件系统设计了~(87)Sr原子光钟的闭环运行的自动化控制程序。实验结果显示,采样时间为3 000 s的光钟频率稳定度为5.7×10~(-17),拟合得到的环内稳定度为5×10~(-15)/τ~(1/2),表明该控制系统的精度符合锶原子光钟的闭环运行要求。

Design and realization of an auto-control system for the closed-loop operation of a strontium atomic clock

An auto-control system was designed and realized for the closed-loop operation of a strontium atomic clock. This closed-loop operation locked an ultra-stable laser to a frequency obtained by averaging two peaks of the spin-polarized spectrum of the hyperfine energy structure of an isotope of ⁸⁷Sr. Firstly, the requirements for automatic control of the closed-loop operation of the ⁸⁷Sr atomic clock were specified, including the controlling signals and their time sequences during laser cooling and trapping of the atoms, the detection of the clock transition spectrum, and the closed-loop operation. Secondly, these specified requirements lead to the design of the physical systems. Finally, the auto-control program was designed using LabVIEW, and data acquisition hardware from National Instruments. The measurements of the frequency stability demonstrated that the in-loop frequency instability is approximately 5×10^-15/τ^1/2, and the frequency instability for 3 000 seconds of sampling time is 5.7×10^-17. These results demonstrate that the designed auto-control system meets the requirements of a strontium atomic clock for closed-loop operation.