基于相干滤波和相干布居数囚禁原理的激光原子钟  

Laser atomic clock based on coherent filtering and coherent population trapping

作　　者：汪中[1] 陈景标[1] WANG Zhong;CHEN Jing-biao(Department of Electronics Engineering and Computer Science,Peking University,Beijing 100871,China)

机构地区：[1]北京大学信息科学技术学院电子学系,北京100871

出　　处：《时间频率学报》2022年第2期124-128,共5页Journal of Time and Frequency

摘　　要：激光原子钟基于相干布居数囚禁(CPT)和激光器模式锁定的基本原理,其谐振腔内仅有两个模式可以振荡,而且这一设计可以使两个纵模振荡频率与特定工作原子的跃迁频率相等,且相互锁定。而且由于激光谐振腔内插入的干涉滤光单元和CPT单元的双重作用,使两个模式的频率间隔精确等于工作原子的基态超精细结构跃迁频率,并且在谐振腔模式中具有最高增益。通过对激光器腔长、增益,以及腔内插入单元的稳定控制,以此方法建成的激光器将有两个稳定的纵模输出,而两纵模之间的拍频将精确等于CPT系统工作原子的基态超精细能级的跃迁频率。直接检测两个纵模的拍频,就可以获得高稳定度的标准频率输出。而且由于其模式锁定过程是一个物理的自动牵引锁定过程,不再像一般原子钟那样依赖于锁定电路和对原子跃迁信号的探测和识别。因此有望获得更高的稳定度。其标准频率的信号强度,信噪比也会大大高于以往方法产生的原子钟输出信号。Our laser atomic clock based on the basic principle of CPT and laser mode locking,in the cavity,there are only two modes in the resonator that can oscillate,and this unique design can make the oscillation frequencies of the two longitudinal modes equal to the transition frequencies of specific working atoms and locked to each other,and their frequency interval equal to the transition frequency of the ground state hyperfine structure of the atom.The reason is that,in the laser atomic clock the dual functions of interference filter and CPT system in the resonator make the tow oscillate modes having the highest gain when their frequency interval exactly equal to the ground state hyperfine transition frequency of the atom.By stabilizing the cavity length,gain and insertion system,the laser built by this method will have two stable longitudinal mode outputs,and the frequency difference between the two longitudinal modes will be exactly equal to the transition frequency of the ground state hyperfine levels of the working atoms of the CPT systems in the cavity.By directly detecting the beat frequency of two longitudinal modes,the standard frequency output with high stability can be obtained.Because the mode locking process is a physical automatic traction locking process,it no longer relies on the locking circuit and the detection and recognition of the atomic transition signal as the general atomic clock does.Therefore,it is expected to obtain higher stability.The signal intensity and signal-to-noise ratio of the standard frequency output are also much higher than those of the atomic clock output signal produced by the previous methods.

关 键 词：原子钟 相干滤波 相干布居数囚禁 干涉滤光片 锁模 

分 类 号：TH714.14[机械工程—测试计量技术及仪器]