强光电离氢原子产生花篮状干涉动量谱的数值研究  

Numerical Investigation of Bouquet⁃Like Photoelectron Momentum Distributions in Strong Field Ionization of Hydrogen

作　　者：张晟华 张贵忠[1,2] 付国跃 史伟 姚建铨[1,2] Zhang Shenghua;Zhang Guizhong;Fu Guoyue;Shi Wei;Yao Jianquan(College of Precision Instrument and Optoelectronics Engineering,Tianjin University,Tianjin 300072,China;Key Lab of Optoelectronic Information Technology,Ministry of Education,Tianjin 300072,China)

机构地区：[1]天津大学精密仪器与光电子工程学院,天津300072 [2]教育部光电信息技术重点实验室,天津300072

出　　处：《中国激光》2023年第5期135-141,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(11674243,11674242);中央高校基本科研基金(3122016D014)。

摘　　要：报道了强激光脉冲电离氢原子诱导的花篮状动量谱(PMDs)的数值模拟研究。采用强场近似理论(SFA)和鞍点近似算法模拟计算了不同激光强度条件下的花篮状动量谱。数值模拟结果表明,花篮状干涉结构电子动量谱源于三种干涉条纹的相互干涉叠加,这三种干涉条纹分别是半圆状阈上电离(ATI)干涉条纹和两种左右对称的周期内干涉(ICI)条纹。后者的干涉条纹随着激光强度的增加而单调变密。依据经典作用相位,深入研究了阈上电离干涉结构和周期内干涉结构的特点,提出了定量描述这两类干涉条纹结构的解析式,所提解析式可以很好地刻画干涉条纹的性质。此外,类比于传统坐标空间的多缝干涉,本文给出了动量空间三缝干涉诱导花篮状动量谱的直观物理图像,该图像有助于理解电子波包干涉的微观机理。Objective In a stronger laser field,electrons move along different paths after ionization.This process involves two phases:first,the electron moves directly to the detector,and second,the ion scatters the other.Interference occurs when the electrons arrive at the detector with the same final momenta.Moreover,an interference structure in the photoelectron momentum distributions(PMDs)appeared.The interference structure encodes the dynamic information of electrons and the structural information of the parent ions,which are vital tools for studying the microscopic states of atoms and molecules in strongfield processes.Generally,these two kinds of ionized electrons are named reference electron:reaching the detector directly and being analogous to the reference light in laser holography,and the signal electron:returning to the parent ion and being scattered off by the ion and reaching the detector eventually,being analogous to the signal light in laser holography.Theoretically,we can obtain the PMDs by solving the timedependent Schrödinger equation(TDSE);however,solving TDSE is difficult because of the microscopic process control to achieve the best nanoscopic physical picture.Therefore,the semiclassical theory becomes an alternative in numerical simulation.The distributed bouquetlike PMDs in momentum domains perpendicular to the laser polarization is relatively weak.However,this interference structure carries the characteristic information of the abovethreshold ionization(ATI)and the innercycle interference(ICI)processes.Methods The study used the strong field approximation(SFA)theory and saddle point approximation method for investigations.Electrons are ionized at the peak of the laser field.In SFA,ionized electrons are affected only by the laser field,whereas the influence of parent ions is negligible.The final state of the ionized electron in the laser field was considered the Volkov state.It is simple to obtain the PMDs from the expression of the wave function amplitude of ionized electrons.We used the saddle poi

关 键 词：非线性光学 光电子全息 花篮状干涉动量谱 阈上电离 周期内干涉 

分 类 号：O437[机械工程—光学工程]