1 中国科学院上海光学精密机械研究所量子光学重点实验室, 上海 201800
2 中国科学院大学材料科学与光电技术学院, 北京 100000
喷泉钟量子化轴磁场的空间均匀性和时间稳定性是制约原子钟输出频率稳定度和不确定度的重要因素。从外磁场屏蔽、磁场线圈设计、线圈电流源稳定性等方面考虑,构建并优化设计了一套可搬运铷喷泉原子钟量子化轴磁场系统。为了消除环境磁场对量子化轴磁场的影响,使用5层坡莫合金磁屏蔽进行外磁场的屏蔽;利用4组对称的补偿线圈,通过计算给予合适的电流,获得喷泉钟内部30 cm原子自由飞行尺度内磁场波动小于1 nT;通过改善C场供电电流方式,从而优化量子化轴磁场的时间稳定性,磁场随时间的波动小于0.1 nT。优化后喷泉钟长期频率稳定度达2.9×10 -16,磁场空间分布不均匀性带来的二阶塞曼频移不确定度为3.4×10 -19,由磁场随时间波动带来的二阶塞曼频移的不确定度为5.1×10 -17。
原子与分子物理学 塞曼效应 超精细结构 原子钟 磁敏跃迁法 光学学报
2021, 41(19): 1902001
Author Affiliations
Abstract
1 Key Laboratory of Quantum Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
In this article, taking advantage of the special magnetic shieldings and the optimal coil design of a transportable Rb atomic fountain clock, the intensity distribution in space and the fluctuations with time of the quantization magnetic field in the Ramsey region were measured using the atomic magneton-sensitive transition method. In an approximately 310 mm long Ramsey region, a peak-to-peak magnetic field intensity of a 0.74 nT deviation in space and a 0.06 nT fluctuation with time were obtained. These results correspond to a second-order Zeeman frequency shift of approximately . This is an essential step in advancing the total frequency uncertainty of the fountain clock to the order of .
Zeeman effect hyperfine structure atomic clock magnetic-sensitive method Chinese Optics Letters
2021, 19(12): 120201
1 中国科学院上海光学精密机械研究所量子光学重点实验室, 上海 201800
2 中国科学院大学, 北京 100049
能够长期自主运行的稳频激光器是喷泉原子钟连续工作的基础。基于铷原子喷泉钟中的780 nm商用半导体激光器,利用嵌入式系统设计了一个长期全自动稳频系统。该系统具有自动识别铷饱和吸收谱线的目标峰、长期锁定频率与意外失锁后的快速重锁的功能。提出了一种动态调整工作点的方法。在激光器长期运行过程中,受温度、湿度和器件老化等因素的影响,目标工作点会随时间发生变化,所提方法可解决该问题。利用该方法,激光器的稳频系统不易失锁,即使失锁也可以快速重新锁回。将所提稳频系统成功应用于可搬运铷喷泉原子钟中,铷喷泉原子钟在搬运后能够快速投入工作,激光频率的长期锁定时间可达一个月以上。激光频率相对于铷饱和参考谱线的频率长期稳定度约为2.3×10 -13,可搬运铷喷泉原子钟的长期稳定度在搬运前后均达到了10 -16量级。
激光器 激光冷却 喷泉原子钟 自动稳频 稳定度 光学学报
2020, 40(22): 2214002
Author Affiliations
Abstract
1 Key Laboratory of Quantum Optics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
A high-performance transportable fountain clock is attractive for use in laboratories with high-precision time-frequency measurement requirements. This Letter reports the improvement of the stability of a transportable rubidium-87 fountain clock because of an optimization of temperature characteristics. This clock integrates its physical packaging, optical benches, microwave frequency synthesizers, and electronic controls onto an easily movable wheeled plate. Two optical benches with a high-vibration resistance are realized in this work. No additional adjustment is required after moving them several times. The Allan deviation of the fountain clock frequency was measured by comparing it with that of the hydrogen maser. The fountain clock got a short-term stability of at 1 s and long-term stability on the order of 10 16 at 100,000 s.
020.3320 Laser cooling 120.3940 Metrology 270.2500 Fluctuations, relaxations, and noise 270.5570 Quantum detectors Chinese Optics Letters
2019, 17(8): 080201
中国科学院上海光学精密机械研究所量子光学重点实验室, 上海 201800
建立了微瓦量级的激光功率自动稳定实验装置，通过自动反馈控制声光调制器的衍射效率，实现了激光功率的自动稳定。激光功率稳定后，激光相对强度噪声得到有效抑制，接近散弹噪声极限，激光功率的长期稳定度优于2×10-5(1000 s)。推导了功率自动稳定系统的环路方程，分析了激光功率稳定环路对相对强度噪声的抑制作用。稳定后的激光应用于积分球冷原子钟的钟跃迁探测，对原子钟稳定度的影响小于1×10-13τ-1/2，积分球原子钟的频率稳定度优于5×10-13τ-1/2(τ为取样时间)。
激光光学 激光稳定 冷原子钟 激光冷却
