摘要
利用三维经典系综模型系统地研究了反向旋转双色椭偏场中Ar原子非次序双电离对椭偏率的依赖。数值结果显示双电离发生的概率随800 nm激光场椭偏率增大而增大,随1600 nm激光场椭偏率增大而减小。这是因为当固定1600 nm激光场椭偏率时,电子的返回概率和碰撞能量随800 nm激光场椭偏率增大而增大。而当固定800 nm激光场椭偏率时,电子的返回概率和碰撞能量随1600 nm激光场椭偏率增大而减小。在两椭圆激光场的长轴沿x方向条件下,当1600 nm激光场椭偏率为0.3时,离子动量分布由x负半轴向x正半轴移动。随着1600 nm激光场和800 nm激光场椭偏率的增大,离子动量分布逐渐在y方向扩展最终形成一个分布于x轴两侧的两层结构。
Nonsequential Double Ionization(NSDI)is a basic physical process of the interactions of strong laser fields with matter.The two electrons involved in NSDI are highly correlated,which provides a simple and effective method for understanding the electron correlation.In the past three decades,the ionization mechanism of NSDI has been studied extensively.Based on the two-hump structure of ion momentum distributions and the disappearance of the“knee”structure in the circularly polarized laser fields,the recollision model has become a very suitable ionization mechanism.The mechanism is divided into three steps.Step 1:An electron in the atom or molecule is ionized in the laser field;step 2:The ionized electron is accelerated in the laser field.When the direction of the laser field changes,the ionized electron may be pulled back and recollide with the parent ion;step 3:After recollision,the returning electron can transfer a part of the energy to the bound electron,and finally,both electrons ionize immediately or with a time delay.In linearly polarized pulses,electrons are driven by electric field force only in one direction.The returning probability is relatively high and thus results in a high double ionization yield.Therefore,early studies mainly focus on linear polarization.In this case,the control of electron dynamics is confined to one dimension.To manipulate electrons in two-dimensional space,recently,much attention has been focused on the combined electric field composed of two pulses,such as the Counter-rotating Two-color Circularly Polarized(CTCP)laser fields.By changing laser parameters,the CTCP fields can control double ionization yield,electron returning direction and returning energy.However,the waveform of the combined electric field formed by the two-colour circularly polarized pulses has multiple-fold symmetry,and the ionized electrons can return from multiple directions.If two elliptically polarized pulses are used to form a combined electric field,the multiple-fold symmetry of the electric field wav
作者
黄诚
苏杰
廖健颖
刘子超
贺佟佟
李盈傧
HUANG Cheng;SU Jie;LIAO Jianying;LIU Zichao;HE Tongtong;LI Yingbin(School of Physical Science and Technology,Southwest University,Chongqing 400715,China;College of Physics and Electronic Engineering,Xinyang Normal University,Xinyang 464000,China)
出处
《光子学报》
EI
CAS
CSCD
北大核心
2023年第11期122-134,共13页
Acta Photonica Sinica
基金
国家自然科学基金(Nos.12074329,12004323,12104389)
西南大学大学生创新创业训练计划项目(No.X202210635104)
信阳师范学院“南湖学者奖励计划”青年项目。
关键词
双色椭偏场
非次序双电离
离子动量分布
电子关联
再碰撞
Two-color elliptically polarized fields
Nonsequential double ionization
Ion momentum distribution
Electron correlation
Recollision
