双变量拉比法制备冷原子及其冷原子碰撞频移的研究  

Investigation of preparing atoms by two variable Rabi method and cold atom’s collisional frequency shift in Cs fountain clock

作　　者：管勇[1,2,3] 刘丹丹 王心亮[1,2] 张辉[1,2,3] 施俊如[1,2,3] 白杨 阮军 张首刚 GUAN Yong;LIU Dan-dan;WANG Xin-liang;ZHANG Hui;SHI Jun-ru;BAI Yang;RUAN Jun;ZHANG Shou-gang(National Time Service Center,Chinese Academy of Sciences,Xi’an 710600,China;Key Laboratory of Time and Frequency Primary Standards,Chinese Academy of Sciences,Xi’an 710600,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院国家授时中心,西安710600 [2]中国科学院时间频率基准重点实验室,西安710600 [3]中国科学院大学,北京100049

出　　处：《时间频率学报》2020年第4期245-252,共8页Journal of Time and Frequency

基　　金：国家重点研发计划资助项目(2016YFF0200202);中国科学院重大科技基础设施维修改造项目(DSS-WX GZ-2020-0005);中国科学院“西部之光”人才培养计划“西部青年学者”资助项目(XAB2018A06)。

摘　　要：冷原子碰撞频移是影响铯喷泉钟频率不确定度性能的主要频移项之一。采用差分法评定该项频移时,其不确定度来源于原子团密度比的误差和高低密度运行状态下的频率波动,分别影响该项频率评定的系统不确定度和统计不确定度。基于单变量拉比法选态的原理,我们发展了双变量拉比法(同时调整选态微波的幅度和频率)制备不同密度比原子团的技术,分析了采用该方法评定喷泉钟冷原子碰撞频移引入的不确定度,实验制备了均匀度3×10-3的不同密度比的原子团,可同时降低冷原子碰撞频移评定的系统不确定度和统计不确定度。The cold collision frequency shift is one of the main frequency shifts in cesium fountain clock.The uncertainty of evaluating the frequency shift by differential method can be deduced from the error of density ratio and the frequency fluctuation of high and low atomic density,which affect the systematic and statistic uncertainties of the frequency shift respectively.Based on the principle of Rabi method of state selection,we develop a bivariate Rabi method,where both the amplitude and frequency are adjustable,to prepare atom clouds with different density ratio.The uncertainty of evaluating the frequency shift by such method is also analyzed,and atom clouds with homogeneous density ratio up to 3×10-3 are realized for different density ratio.The results can be used to reduce both systematic and statistic uncertainties of the evaluation of collision frequency shift.

关 键 词：铯原子喷泉钟 冷原子 冷原子碰撞频移 

分 类 号：O562.5[理学—原子与分子物理]