基于腔内冷却的原子钟分布式腔相移分析  

Distributed Cavity Phase Shift Analysis of Atomic Clocks Based on Intracavity Cooling

作　　者：邓思敏达 任伟[1,2,3] 项静峰 吕德胜 Deng Siminda;Ren Wei;Xiang Jingfeng;Desheng Lü(Aerospace Laser Technology and Systems Department,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;Key Laboratory of Quantum Optics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院上海光学精密机械研究所空天激光技术与系统部,上海201800 [2]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 [3]中国科学院大学材料与光电研究中心,北京100049

出　　处：《中国激光》2024年第21期249-255,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金青年基金(12004401,12304550)。

摘　　要：分布式腔相移是影响冷原子微波频标频率不确定度的关键因素之一,也是高性能原子钟频率不确定度评估中的重要研究内容。提出了一种基于三维有限元仿真和蒙特卡罗遍历原子技术的分布式腔相移计算方法,分析计算了分布式腔相移对小型化原子钟的影响。结果显示,当Ramsey线宽为10 Hz时,不同原子团温度下分布式腔相移的不确定度均优于2×10^(-16)。因此该小型化原子频标方案的长期稳定度不会受到分布式腔相移的影响,在小型化原子钟中长期性能方面具有显著的优势。该计算方法还可以推广至结构复杂的矩形腔、环形腔以及原位探测微波腔等,对于分析原子钟分布式腔相移和优化微波腔设计具有重要的应用价值。Objective The development of laser-cooling technology has advanced cold-atomic-frequency standards,thus enhancing the precision of defining a second to 10-16.Additionally,the second definition with a frequency uncertainty of 10-19,which offers even greater accuracy,is anticipated to be established in the optical-frequency standard.The cold-atomic-frequency standard offers a higher frequency accuracy and a lower frequency drift rate compared with the classical atomic-frequency standard,thereby providing higher long-term stability.Among the various physical factors affecting the accuracy of atomic-frequency standards,the distributed-cavity phase shift is one of the most important sources of uncertainty and a key factor to be considered in the miniaturization of cold-atomic frequency standards. Currently, the analysis and calculation of the distributed-cavity phase shift primarily involves the Fourierdecomposition of three-dimensional phase distributions in column coordinates. This method accurately solves the phase distribution ofmicrowave cavities with simple structures and the corresponding frequency shifts. However, for phase distributions in rectangularcavities, annular cavities, and cylindrical cavities with multiple openings in the sidewalls, which are relatively complex, this methodrequires remodeling and is complicated. Rapid advancements in computer technology have enabled rapid three-dimensional finiteelementsimulations that accurately simulate the phase distribution in microwave cavities. This facilitates the optimization ofmicrowave-cavity designs, thus reducing the effect of the distributed-cavity phase shift.Methods This study examines the phase distribution of an intracavity-cooling falling-detection atomic clock based on threedimensionalfinite-element simulations. Initially, each atom is assigned a position based on a Gaussian distribution and specified withan initial velocity based on the Maxwell – Boltzmann distribution. The direction of the initial velocity is assumed to be completelyrandom, an

关 键 词：冷原子频标 频率不确定度 分布式腔相移 频率稳定度 

分 类 号：O562[理学—原子与分子物理]