Correlated Distribution And Microscopic Dynamic Process Of Atomic Double Ionization In Strong Laser Field

Electron-electron correlation is a universal phenomenon in the microscopic world.It was a major impact in formation of chemical bounds in chemical reaction,the phenomenon of superconductivity,and the solid state properties,but also an important part of attosecond physics.Strong field non-sequential double ionization(NSDI)process provides a basic model for the study of electron-electron correlation,and became a frontier of the strong-field laser physics.In this paper,using the Monte Carlo method based on the Newton equation,the double ionization of rare gas atoms in intense laser field,we established a scaling law of double ionization,and tested the role of multiple collision by using few-cycle laser pulses of special envelope.The main contents of this thesis are as follows:(1)Illuminated by the scaling law in single ionization process,we proposed for the first time a scaling law of NSDI:the momentum distribution of the correlated electrons from an atom driven by a laser field of frequency ? and intensity I is the same as that from another atom irradiated by the laser field of frequency kco and intensity k3I.The scaling ratio k equals to the ratio of the second ionization potentials of two atoms.With the momentum distribution of the correlated electrons,we firstly verify the cubic dependence of the laser intensity with the scale factor,and then determine the scaling ratio which is the ratio of the second ionization potentials between two atoms,and finally verify the scaling law can be applied to Ar,Ne,He and Mg atoms.(2)We report that the nonsequential double ionization(NSDI)yield of O2 target can be enhanced significantly in acounterro-tating circularly polarized two-color driving field.The field is composed of a fundamental frequency and its third harmonic,and the combined electric field traces out a four-leaf clovers pattern.The first electron ionized by such field has more chances to collide with the valence electrons in O2 molecules,and the secondly ionized electron tends to be excited firstly.The NSDI yield can be enhanced as much as three orders of magnitude.Both the NSDI yield and the underlying electronic behavior can be controlled by varying the field ratio of two colors.The proposed scheme provides an efficient way to study the excitation effects of bound electrons.