冷原子成像谱仪中靶表征及光电离研究  

Target Characterization and Photoionization Study in Cold Atom Imaging Spectrometer

作　　者：马祎璇 李任远 袁俊阳 孟秋香 马欢玉 阮舒舒 张逸竹[1,4] 阎天民 沈镇捷 王新成 江玉海 Ma Yixuan;Li Renyuan;Yuan Junyang;Meng Qiuxiang;Ma Huanyu;Ruan Shushu;Zhang Yizhu;Yan Tianmin;Shen Zhenjie;Wang Xincheng;Yuhai Jiang(Shanghai Advanced Research Institute,Chinese Academy of Sciences,Shanghai 201210,China;School of Physical Science and Technology,Shanghai Tech University,Shanghai 201210,China;University of Chinese Academy of Sciences,Beijing 100049,China;Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering,Key Laboratory of Education,Tianjin University,Tianjin 300072,China)

机构地区：[1]中国科学院上海高等研究院,上海201210 [2]上海科技大学物质科学与技术学院,上海201210 [3]中国科学院大学,北京100049 [4]天津大学精密仪器与光电子工程学院太赫兹研究中心,天津300072

出　　处：《中国激光》2020年第6期98-107,共10页Chinese Journal of Lasers

基　　金：国家自然科学基金(11827806,11874368,61675213)。

摘　　要：将冷原子、超快和强激光技术结合,本课题组最近成功研发了一种新型磁光阱反冲离子动量谱仪(MOTRIMS)装置。介绍了MOTRIMS工作原理,使用吸收成像法和光电离法对靶的密度、温度和速度进行分析标定,得到三维MOT靶的温度为(130±30)μK,速度为(0.1±0.1)m/s,密度约为10^9 atom/cm^3,二维MOT和molasses靶的密度分别约为10^7 atom/cm^3和10^8 atom/cm^3。对比热蒸气靶,在离子飞行方向上冷原子靶的动量分辨率提高了约14倍,飞行时间谱的质量分辨率高达3000。利用800 nm飞秒激光探测Rb^+的三维动量分布,在低激光强度10^11 W/cm^2下观测到明显的阈上电离现象,表明铷原子有很大的阈上电离截面。MOTRIMS具有高分辨离子动量分布全空间成像能力,是研究金属原子强场量子微观动力学的新工具。Recently,the magneto-optical trap recoil ion momentum spectroscopy(MOTRIMS)device was successfully fabricated in combination with cold atoms and ultrafast and super intense laser technology.Herein,the MOTRIMS principle was introduced,and the density,temperature,and velocity of the target were analyzed and calibrated using the absorption imaging method and photoionization method.Results indicated that the temperature of the 3D MOT target is(130±30)μK,velocity is(0.1±0.1)m/s,density is approximately 10^9 atom/cm^3,and the densities of the 2D MOT and molasses targets are approximately 10^7 and 10^8 atom/cm^3,respectively.Compared with the hot vapor target,the momentum resolution of the cold atom target in the direction of ion flight improved by approximately 14 times and the mass resolution of the time-of-flight spectroscopy is up to 3000.Moreover,the three-dimensional momentum distribution of Rb^+was detected using 800-nm femtosecond laser;an obvious above-threshold ionization phenomenon was observed at a low laser intensity of 10^11 W/cm^2,indicating that Rb^+atoms exhibit a large above-threshold ionization cross section.MOTRIMS is a new tool for investigating the strong field quantum micro dynamics of metal atoms owing to its ability to image the momentum distribution of ions in full space.

关 键 词：原子与分子物理学 磁光阱反冲离子动量谱仪 离子高分辨动量分布 铷原子激光冷却 强场电离 

分 类 号：O562[理学—原子与分子物理]