超透镜聚焦光环的产生及其在冷分子光学囚禁中的应用  

Generation of focusing ring of metalens and its application in optical trapping of cold molecules

作　　者：李军依 叶玉儿 凌晨[1] 李林[1] 刘泱 夏勇[1] Li Jun-Yi;Ye Yu-Er;Ling Chen;Li Lin;Liu Yang;Xia Yong(State Key Laboratory of Precision Spectroscopy,School of Physics and Electronic Science,East China Normal University,Shanghai 200241,China;School of Physics and Astronomy,Sun Yat-sen University,Zhuhai 519082,China)

机构地区：[1]华东师范大学物理与电子科学学院精密光谱科学与技术国家重点实验室,上海200241 [2]中山大学物理与天文学院,珠海519082

出　　处：《物理学报》2021年第16期297-304,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:91836103,11974434);广东省自然科学基金(批准号:2020A1515011159)。

摘　　要：超表面可以对入射光场的相位、偏振、幅度等自由度进行精确调控,为发展下一代基于量子态片上实验平台提供了一种新途径,具有重要的应用前景.本文提出了一种新型的超表面结构,即具有不同占空比的硅结构光栅单元构成的超透镜,在焦平面上可形成聚焦光环.研究了在焦平面上环形光场的强度分布和不同数值孔径超透镜的聚焦特性.采用这种超透镜聚焦光环来构建一个氟化镁(MgF)分子的光学存储环,计算了MgF分子在聚焦光场中所受的光学势和偶极力,对MgF分子束在存储环运动过程进行了Monte-Carlo模拟.研究结果表明,设计的超表面结构具有很好的聚焦特性,聚焦光环的光场强度比入射光增强了55.1倍;同时可以实现对MgF分子的装载并囚禁在表面存储环内.Metasurface can precisely control degrees of freedom of the phase,polarization,and amplitude of the incident light field.It provides a new way to develop the next generation of the experimental platform of quantum-state manipulation on-chip,which has important application prospects.This paper proposes a new type of metasurface structure,that is,a metalens composed of silicon grating elements with different duty ratios that can form a focusing ring on the focal plane.The intensity distribution of the ring light field in the focal plane and the focusing characteristics of metalens with different numerical apertures are studied.An optical storage ring of magnesium fluoride(MgF)molecule is constructed by using this kind of metalens focusing ring.The optical potential and dipole force of the MgF molecule in the focused light field are calculated,and the dynamic process of MgF molecule motion in the storage ring is simulated by the Monte-Carlo method.The research results show that for the incident light of 1064-nm radially polarized light,the designed metasurface structure has good focusing characteristics,and the light field intensity of the focusing ring is 55.1 times stronger than that of the incident light.The focal length of the annular light field is 22μm and the full width at half maximum of the light intensity distribution in the focal plane is 0.8μm,and the numerical aperture of the hyperlens is 0.69.The maximum dipole potential of MgF molecules in the light field is 32μK,which can realize the loading of MgF molecules and trap them in the surface storage ring.

关 键 词：超表面 超构透镜 光学囚禁 光栅 

分 类 号：O561[理学—原子与分子物理]