Xie Weibin, Wang Qing, He Xuan, Xiong Zezheng, Chen Nan, Fang Shengwei, Qi Xianghui, Chen Xuzong
Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China.
Rev Sci Instrum. 2020 Sep 1;91(9):094708. doi: 10.1063/1.5144478.
In this paper, we present a linewidth locking method to control the microwave power in optically pumped cesium-beam frequency standards. The responses of optically pumped cesium-beam tubes and classical cesium-beam tubes are analyzed and compared against the power of the microwave field. Due to the wide probability distribution of atomic velocity resulting from the optical state preparation and detection, the linewidth of the Ramsey pattern is sensitive to the microwave power. The results can be used to control the microwave power instead of using the traditional extremum method. The advantages of the new method are discussed, and we named this new method the linewidth locking method. When the microwave power is well controlled at a low level by the linewidth locking method, the frequency stability of cesium-beam clocks will be improved to a certain degree for the reduction of the Ramsey pattern linewidth. In experiment, using the linewidth locking method, the Allan deviation of our optically pumped cesium-beam frequency standard is 2.64×10/τ and continues until the averaging time exceeds 1 × 10 s, which is 17% better than that using the traditional extremum method.
在本文中，我们提出了一种线宽锁定方法来控制光泵铯束频率标准中的微波功率。分析并比较了光泵铯束管和传统铯束管对微波场功率的响应。由于光态制备和检测导致原子速度的概率分布较宽，拉姆齐条纹的线宽对微波功率敏感。该结果可用于控制微波功率，而不是使用传统的极值法。讨论了新方法的优点，我们将这种新方法命名为线宽锁定方法。当通过线宽锁定方法将微波功率很好地控制在低水平时，由于拉姆齐条纹线宽的减小，铯束钟的频率稳定性将在一定程度上得到提高。在实验中，使用线宽锁定方法，我们的光泵铯束频率标准的阿伦偏差为2.64×10⁻¹¹/τ，并且一直持续到平均时间超过1×10⁵秒，这比使用传统极值法提高了17%。
