基于光锁相环的稳频深紫外激光系统  

Frequency-Stabilized Deep Ultraviolet Laser System Based on Optical Phase-Locked Loop

作　　者：刘琪鑫 张晔 孙剑芳[1] 徐震[1,2] Liu Qixin;Zhang Ye;Sun Jianfang;Xu Zhen(Key Laboratory of 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)

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

出　　处：《中国激光》2023年第7期153-160,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(11874371,91436105,12104474);中国科学院战略性先导科技专项(XDB21030200);上海市科技计划项目(22ZR1471000)。

摘　　要：介绍了一种利用光锁相环技术实现频率稳定的深紫外激光系统,包含两台253.7 nm四倍频激光器,用于汞原子在二维磁光阱和三维磁光阱的激光冷却。其中,一台深紫外激光器锁定在汞原子的饱和吸收谱线上,用于产生二维磁光阱的冷却光和推送光;另一台深紫外激光器通过1014.9 nm的半导体种子激光之间的光锁相环实现频率稳定,用于产生三维磁光阱的冷却光和探测光,并通过前馈方法将频率切换时间减小到原来的1/23。该系统可以大范围地调整深紫外激光器的频率,高效地利用紫外激光功率,并降低了实验装置的复杂性,从而满足了汞原子激光冷却实验的要求。同时,所提方法适用于其他深紫外激光系统。Objective Recently,an increasing number of frequency-stabilized deep ultraviolet (DUV) lasers have been used in research on the laser cooling of atoms and ions,such as H,Hg,Cd,Mg,Be~+,In~+,and Mg~+.Mercury atoms,which are the heaviest stable lasercooled atoms,have been widely studied owing to their unique nature.Mercury atoms have a low sensitivity to blackbody radiation,and the mercury lattice clock is one of the recommended secondary representations of the second in the international system of units.It is also a good candidate to test the variation in the fine-structure constant and to measure the permanent electric-dipole moment of the electron.For the laser cooling of neutral mercury atoms,it prefers to adopt a two-dimensional magneto-optical trap (2D-MOT) plus three-dimensional magneto-optical trap (3D-MOT) configuration to improve the loading rate.This configuration requires a higher deep ultraviolet laser power,which is limited by DUV damage to optical elements.Here,we present a frequency stabilization laser system based on an optical phase-locked loop (OPLL) between infrared seed lasers,which can easily adjust the laser frequency over a wide range and efficiently use DUV laser power.Methods The ~1S_0→~3P_1 transition at 253.7 nm is used for the laser cooling of mercury atoms.In the 2D-MOT plus 3D-MOT configuration,the frequencies of the 2D-MOT,push beam,and 3D-MOT must be independently adjustable.Therefore,in this study,two 253.7 nm frequency-quadrupled DUV lasers are used,and a frequency-stabilized DUV laser system with optical phase-locked loop technology is developed for the laser cooling of neutral mercury atoms.One DUV laser is locked on the saturated absorption spectroscopy and is used as the cooling laser of the 2D-MOT.Three acousto-optic modulators (AOMs) are used to set the detuning of each beam.Another DUV laser is frequency-stabilized by an OPLL between the semiconductor seed lasers at 1014.9 nm and is used as the cooling laser of the 3D-MOT without passing through any additional frequency sh

关 键 词：激光器 汞原子 激光冷却 深紫外激光 光锁相环 

分 类 号：O436[机械工程—光学工程]