原子喷泉中基于电光调制的激光移频与稳频  

Laser Frequency Shift and Stabilization of Atomic Fountain Based on Electro-Optic Modulation

作　　者：赵伟靖 李耀[1,2] 董日昌 魏荣 Zhao Weijing;Li Yao;Dong Richang;Wei Rong(Key Laboratory for Quantum Optics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;University of Chinese Academy of Sciences,Beijing 100049,China;Innovation Academy for Microsatellites of Chinese Academy of Sciences,Shanghai 200120,China)

机构地区：[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 [3]中国科学院微小卫星创新研究院,上海200120

出　　处：《光学学报》2023年第19期219-226,共8页Acta Optica Sinica

基　　金：中国科学院战略性先导科技专项(B类)(XDB21030200);国家重点研发计划(2021YFA0718303)。

摘　　要：激光稳频是影响原子喷泉系统性能的关键技术。提出了一种应用于原子喷泉系统的激光稳频优化方案。该方案将激光冷却过程中采用的移频方法应用到稳频系统中,通过光纤电光调制的方法产生边带,并将频率锁定在边带的饱和吸收峰上。同时应用大光斑饱和吸收模块,改善饱和吸收信号和误差信号的信噪比。利用85Rb原子喷泉系统主光路的探测光,通过1.035 GHz的移频,实现从85Rb饱和吸收峰到87Rb饱和吸收峰的转移锁定,并在85Rb喷泉系统中观测到冷原子云信号。锁定后的信号可实现较长时间的稳定工作。该方案通过控制电光调制频率,还有望实现激光冷却实验范围内的任意频率锁定,具有重要的应用价值。Objective In recent years,atomic frequency standards(AFSs)have been significantly improved and widely applied in measurement and transportation.The uncertainty of fountain AFSs has reached 10-16,and that of optical AFSs is much higher at 10-19,so AFSs are expected to replace Cs as a new definition of second.The development of AFSs is inseparable from the improvement of laser frequency stabilization.Narrow and ultra-narrow line-width lasers based on the frequency stabilization technology play significant roles in capturing and cooling atoms and ions,and trapping photons.Saturated absorption is widely employed in the frequency stabilization of AFSs because of its simple operation,high resolution,and the elimination of Doppler broadening.It is a technology commonly adopted in the microwave domain of atomic fountain clocks.The saturated absorption frequency stabilization of the atomic fountain clock is realized by locking a specific saturation absorption transition peak.The saturated absorption spectrum signal is modulated and demodulated to produce an error signal,and then a specific feedback signal is generated based on the error signal to control the laser output frequency.According to the output frequency,a series of modulation and frequency shifts are carried out to realize capturing,cooling,launching,and other functions which are required by the cold atom experiment.Generally,atoms have multiple saturated absorption peaks with only one involved in frequency locking,and unselected saturated absorption peaks cannot be utilized.Methods We propose an optimized method of laser frequency stabilization based on AFSs.This method applies the frequency control in laser cooling to the frequency stabilization system and realizes the transfer locking between different saturated absorption transition peaks.The sidebands are generated by fiber electro-optic modulation.Since the zero-order diffraction light cannot meet the frequency shift requirement,the fountain system generally takes+1(or-1)order diffraction light as the eff

关 键 词：原子喷泉 电光调制 移频 饱和吸收 稳定度 

分 类 号：O562.2[理学—原子与分子物理]