Theoretical Study Of The Phase Effect On Above-threshold Ionization And Nonsequential Double Ionization Of Atomic Target In Intense Laser Fields

With the development of the technology,the key point of the scientific research changes from observation and understanding to control.The researchers pay more attention to micro field,and it becomes one of the most significant projects in modern physical research.Since the advent of laser technology,the laser pulse develops in the direction of stronger intensity and shorter pulse width.And the research on phenomenon which generated by the interaction between laser field and target matter has attracted much attention.However,these phenomena have been observed in experimental until the late of last century.Thus,the investigation on the above complicated phenomena is the frontier issue in strong field physics.In particular,the influence of different laser pulse on these phenomena and the underlying physical mechanism remains to be solved.In addition,how to control the movement of the electrons is another frontier topic.In this thesis,we focus on the ionization process of the atoms in strong field physics.By solving the time dependent Schrodinger equation(TDSE)and adopting the quantum trajectory Monte Carlo(QTMC)model,we simulate the distribution of the momentum and propose the scheme to control the motion of the electron by the laser field.And we systematically investigate the ionization channel and the recollision process of the NSDI by adopting the classical ensemble method.The detail of the research are listed as follow:The ionization process of He atoms is simulated by solving the time dependent Schrodinger equation under the ionization gating with different relative phases.Our results show that the relative phase can affect the structure of the interference pattern,which change from only spider-like structure to both spider-like structure and ring-like structure.Meanwhile,the whole photo-electron momentum distribution moves along the x-axis of the photoelectron momentum with increasing the relative phase and the directionality of the spider-like structure also changed.The QTMC simulation can reproduce the interference well.Adopting the QTMC analysis,we illustrate the change of the interference structure and its directionality in the photoelectron momentum spectra.Finally,we find that the emission angle of the electron can be affected by the relative phase of the ionization gating.The carrier-envelop-phase(CEP)dependence of photoelectron energy spectra of atomic He is investigated with spatially inhomogeneous field.The result shows that the higher energy structure(HES)is sensitive to the CEP,which is caused by the slope of the trajectories changing with the CEP.Finally,we can see that the current of the photoelectron can also be controlled by CEP.The NSDI of Ar in a pair of two-color elliptically polarized laser field is investigated.We study the relative phase effect of NSDI and distinguish two particular recollision channel by the delay-time.The numerical results indicate that the shape of the electric field and the correlation effect can both be affected by the relative phase.Finally,the recollision channel can also be controlled by the relative phase.We theoretically study the NSDI of Ar in a 45° cross-linearly-polarized two-color laser field with different phase delays.By tracing the classical trajectories of the NSDI process,we find that the single-recollision and the double-recollision both occur.By analyzing the temporal characteristics of the ionization process,we explain the changing of the probability of the double ionization.And the transfer energy is investigated with different phase delays.