二维强激光场中原子分子电离和谐波辐射的应用(特邀)  

Application of Atomic and Molecular Ionization and Harmonic in a Two-dimensional Strong Laser Field(Invited)

作　　者：张春艳 车佳殷 张俊顺 康鑫 李卫艳 陈彦军[2] ZHANG Chunyan;CHE Jiayin;ZHANG Junshun;KANG Xin;LI Weiyan;CHEN Yanjun(Hebei Key Laboratory of Optoelectronic Information and Geo-detection Technology,School of Mathematics and Science,Hebei GEO University,Shijiazhuang 050031,China;College of Physics and Information Technology,Shaanxi Normal University,Xi′an 710119,China)

机构地区：[1]河北地质大学数理教学部河北省光电信息与地球探测技术重点实验室,石家庄050031 [2]陕西师范大学物理学与信息技术学院,西安710119

出　　处：《光子学报》2024年第6期26-38,共13页Acta Photonica Sinica

基　　金：国家自然科学基金(No.12174239);河北地质大学国家预研项目(No.KY2024YB08),河北地质大学校内青年项目资助(No.QN202229)。

摘　　要：二维激光场具有高分辨能力,为人们在阿秒时间尺度探测和调控物质中电子的超快运动提供了可能。相较于原子,分子具有更多自由度,在强激光场中会呈现出许多新效应。本文介绍了利用强正交偏振双色激光场和椭圆偏振激光场中原子分子的电离和高次谐波辐射分辨电子超快动力学、探测分子空间结构、合成阿秒脉冲链等相关研究。分析了库仑效应、双中心干涉效应、固有偶极效应等对分子电离和谐波辐射的重要影响。通过原子在正交偏振双色场中的强场电离定义了库仑效应诱导的电离时间延迟,解释了双色场中原子光电子谱的上下不对称结构、极性分子光电子谱的各向异性、高次谐波辐射电子轨道时域性质的重要改变。对椭圆偏振激光场中原子强场电离的研究构建了描述库仑诱导电离时间延迟的基本理论模型,基于该模型分辨了椭偏场中极性分子固有偶极对电离的贡献、量化了正交双色场中原子光电子谱的特征结构位置。利用正交偏振双色场中对称分子光电子谱在特定分子取向角下呈现的不对称结构,以及椭偏场中对称分子光电子谱对分子取向角的灵敏依赖实现了对分子空间结构信息的探测。凭借正交双色场中对称分子产生的高次谐波对分子取向角的依赖特性合成了单周期只释放一次的阿秒脉冲链,以及利用小椭偏率激光场中分子产生的高椭偏谐波合成了明亮的超短极紫外脉冲。本文内容将深化人们对正交偏振双色场和椭圆偏振激光场中原子分子电离和谐波辐射机制与规律的认识,为利用二维激光场分辨和控制电子超快动力学的实验研究提供理论参考。The study of strong field physics provides an important scientific foundation for the development of attosecond optics.The interaction of strong laser fields with atoms and molecules produces rich ultrafast dynamic processes,such as above-threshold ionization,High-Order Harmonic Generation(HHG),non-sequential double ionization,and so on.People have further applied these processes to ultrafast detection,developing techniques such as attoclock that can be used to study tunneling time,high-order harmonic spectroscopy that can monitor scattered electron trajectories,attosecond streaking that can measure Wigner time delay.Compared with atoms,molecules have more degrees of freedom and will exhibit many new effects under the action of strong laser fields,such as two-center interference,excited-state effect,permanent dipole effect,and so on.These effects are often coupled with each other and difficult to distinguish.Research has found that compared to linearly-polarized laser fields(where the polarization direction of the laser field is in one direction),two-dimensional polarized laser fields(where the polarization directions of the two fields are perpendicular to each other)exhibit higher resolution,allowing people to detect and control ultrafast electron motion in atoms and molecules at the attosecond time scale.This paper introduces the research on the resolution of electron ultrafast dynamics,detection of molecular spatial structure,and synthesis of attosecond pulse chains using strong field ionization and HHG of atoms and molecules in strongly orthogonal Polarized Two-Color(OTC)laser fields and elliptically polarized laser fields.The specific content is summarized as follows:This paper introduces the use of the strong field ionization photoelectron momentum distribution(PMD)of atoms in OTC fields to distinguish the contributions of long and short electron orbitals(corresponding to re-scattered ionization and direct ionization electrons,respectively)to ionization.By comparing the real-time ionization probability curv

关 键 词：二维激光场 阿秒测量 强场电离 高次谐波 库仑效应 

分 类 号：O437[机械工程—光学工程]