基于多能级速率方程的CaH分子三维磁光囚禁模型  

Three-dimensional magneto-optical trapping model of CaH molecule based on multi-energy-level rate equation

作　　者：王月洋 尹俊豪 严康 林钦宁 庞仁君 王泽森 杨涛 印建平[1] Wang Yue-Yang;Yin Jun-Hao;Yan Kang;Lin Qin-Ning;Pang Ren-Jun;Wang Ze-Sen;Yang Tao;Yin Jian-Ping(State Key Laboratory of Precision Spectroscopy,East China Normal University,Shanghai 200062,China)

机构地区：[1]华东师范大学精密光谱科学与技术国家重点实验室,上海200062

出　　处：《物理学报》2022年第16期119-132,共14页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11834003,11874151)资助的课题。

摘　　要：分子激光冷却与磁光囚禁在超越标准模型的新物理与新机制探索、超冷化学与冷分子碰撞等诸多领域中有着广泛的应用前景.CaH分子的某些态之间具有高度对角化的弗兰克-康登因子,因此早在2004年就被提出作为激光冷却与磁光囚禁的候选分子之一.利用速率方程并考虑双频效应的影响,本文计算了A~2Π_(1/2)←X~2Σ~+与B~2Σ~+←X~2Σ~+跃迁中CaH分子磁光阱内阻尼力和囚禁力的大小,分析了四频率组分和多频率组分激光设置下CaH分子磁光囚禁时的冷却和囚禁效果.结果发现,A~2Π_(1/2)←X~2Σ~+跃迁中,CaH分子在多频率组分激光设置下可获得更大的阻尼力和囚禁力,从而有利于实现CaH分子磁光阱.以上工作不仅证明了CaH分子磁光囚禁的可行性以及为实验探索提供了必要的理论支持,同时也为超冷分子碰撞、极性冷分子BEC、基于极性冷分子的精密测量物理(如电子电偶极矩精密测量)等奠定了重要的研究基础.Laser cooling and magneto-optical trapping of molecules is regarded as one of the state-of-the-art research fields in physics,which possesses broad applications in exploring fundamental physics beyond the Standard Model,quantum many-body physics,cold/ultracold chemistry and collision studies and so forth.Owing to the characteristic of highly diagonal Franck-Condon factors,lower saturation irradiance and larger scattering rate,the CaH molecule has been proposed as a promising candidate for laser cooling and magneto-optical trapping ever since 2004.Taking advantage of the multi-energy-level rate equation as well as the dual frequency effect,we evaluate the damping and trapping forces contained in the optical transitions of A~2Π_(1/2)←X~2Σ^(+) and B~2Σ^(+)←X~2Σ^(+),analyze the cooling and trapping performance for different laser polarization sets,power values and detunings of four laser components,and determine the variations in the damping and trapping forces due to an additional frequency component.It is discovered that if the laser polarization is set to be σ^(-)σ^(+)σ^(+)σ^(+)σ^(+),the detuning for the second laser component is Γ while the detuning of other components are set to be-2Γ,and the laser power is set to be 150 mW,one can obtain a damping acceleration of 28000 m/s~2,and a trapping acceleration of 19000 m/s~2 for the transition of A~2Π_(1/2)←X~2Σ^(+),both of which reach the optimal values under the current scope of the research and exhibit better performance than the CaF molecule.Our results,on one hand,not only offer an ideal method to comprehend the CaH MOT in theory but also help design the CaH MOT experiment or even achieve the Bose-Einstein condensation(BEC) of cold diatomic molecules.On the other hand,alkaline-earth-metal monohydrides(AEMHs) such as CaH,SrH and BaH are well-known for their permanent electric dipole moment,therefore these trapped diatomic molecules can be utilized to untangle the mechanism of dipole-dipole interaction,thus paving the way to realizing the molecula

关 键 词：冷分子 激光冷却与磁光囚禁 CaH分子 

分 类 号：O561[理学—原子与分子物理]