E-E Recollision Dynamics Of Nonsequential Double Ionization With Mid-Infrared Laser Field

With the development of ultrafast laser technology and the the improvement of optical pulse mode-locked amplification(OPCPA)in recent years,mid-infrared laser pulses have been obtained experimentally,making it a new trend to study the dynamic process of the correlated electrons by the application of this new type of light field.The study of the nonsequential double ionization(NSDI)is a hot topic in the field of atomic and molecular photophysics.The results show that there are many ionization channels in NSDI,such as direct impact ionization,collision excitation ionization and collision double excitation ionization,which makes it inconvenient to study the dynamics of the correlated electrons of NSDI.Recently,the research has shown that the ionization channel of NSDI is single and the return energy of electron wave packet is high in midinfrared laser field,which is helpful to reveal the ultrafast dynamics of the correlated electrons and its regulation.In this paper,we investigated the nonsequential double ionization(NSDI)of atoms(Xe)by laser pulses with classical ensemble model.The content mainly contains two parts,which one is e-e recollision dynamics of nonsequential double ionization with midinfrared laser field by many-cycle laser pulses and the other is electron correlation dynamic of NSDI by few-cycle laser pulses.With a classical ensemble model,we have investigated that the recollision dynamics of correlated electron from nonsequential double ionization with 3200 nm in mid-infrared laser field.The results show that for the mid-infrared laser fields,it is common to extremely asymmetric energy sharing of the two electrons at recollision.To control the intensity of the mid-infrared laser field makes it effective to control the energy sharing of the two electrons,and that phenomenon can be obviously shown in the momentum spectrum of correlated electron.Further,we diagnose the recolliding electron and the bound electron separately by tracing the classical trajectories.It shows that the recolliding electron often obtains a higher energy at recollision but achieves a smaller final longitudinal momentum due to the postcollision velocity.In contrast,the bound electron often obtains a lower energy at recollision but achieves a bigger final longitudinal momentum because of nuclear boomerang.By using a classical ensemble model,we have investigated the correlation behavior of the electrons from NSDI of Xe atoms with mid-infrared laser field by few-cycle laser pulses with the laser wavelength 3100 nm.The results show the return energy of the electron can be regulated and controlled in the wider range.The returning pathway of the electron can be effectively manipulated.Some of the collision happened near the peak of the mid-infrared laser field resulting a obvious curved structure in the momentum spectra of the final-state correlated electron.In addition,we also found that the laser phase at the recollision strongly depends on CEP.The rich details of NSDI is intuitively revealed by back analysis of the classical trajectories.