氦原子贝塞尔涡旋光电离的理论研究  

Theoretical study on photo-ionization of helium atoms by Bessel vortex light

作　　者：赵婷[1] 宫毛毛 张松斌 Zhao Ting;Gong Mao-Mao;Zhang Song-Bin(School of Physics and Information Technology,Shaanxi Normal University,Xi’an 710119,China)

机构地区：[1]陕西师范大学物理学与信息技术学院,西安710119

出　　处：《物理学报》2024年第24期99-106,共8页Acta Physica Sinica

基　　金：中央高校基本科研业务费(批准号:GK202304006);国家自然科学基金(批准号:11934004,12374238,11974230)资助的课题.

摘　　要：涡旋光携带额外的轨道角动量,在与原子分子相互作用时能揭示更深层次的动力学信息.本文基于一阶Born近似构建了涡旋光电离原子分子的理论计算框架,并以氦原子为例进行详细计算和分析.系统地研究了涡旋光引起的光电离截面如何随入射能量及光电子发射角度变化,特别分析了位于涡旋光中心相位奇点的电离现象,揭示了涡旋光在引发光电离过程中的独特行为模式,为进一步研究涡旋光电离过程及其应用奠定了一定的理论基础.Owing to vortex light possessing the additional orbital angular momentum,its interaction with atoms and molecules can reveal in more depth insights into dynamics than the plane wave light.This paper aims to establish a theoretical framework for the photoionization of atoms and molecules by Bessel vortex light.In the case of macroscopic gas target,helium atoms are randomly dispersed around the entire region of the Bessel vortex beam.The final photoionization cross-section is not dependent on the angular momentum of the vortex light,but depends on the opening angle of the Bessel vortex light.This paper systematically computes the variation of photoionization cross-section with photon energy and the angular distributions of photoelectrons under different geometric conditions.The computation results demonstrate that there is a significant difference in the photo-ionization cross-section between vortex light and plane wave light.In order to further investigate the characteristics of the phase singularity of the vortex light(when the light intensity reaches zero),this paper further calculates the photo-ionization of the vortex light with opening angles of 5°,30°,and 60°at the phase singularity,respectively.The results indicate that the angular distribution of photoelectrons at these three angles is significantly dependent on the orbital angular momentum and the opening angle of the vortex light,and the calculated absolute cross-section does not equate to zero.This represents an important distinguishing feature of the Bessel vortex light when interacting with atoms,distinguishing it from the plane wave.This work lays the foundation for further studying vortex light photo-ionization and their applications.

关 键 词：涡旋光 相位奇点 光电离 光电子角分布 

分 类 号：O562[理学—原子与分子物理]