Study Of The RABBITT-like Interference Structures Of Atoms Ionized By Two-color Laser Pulse

The interaction between material and strong laser pulse has been one of the research hotspots since the first laser came into the world.With the progress of laser techniques during these years,more and more experiments are conducted with multi-color laser pulse to obtain more precise control of the dynamic process of photoelectron ionization.Based on multi-color experiments,different methods have been developed to detect the dynamic process of electron ionization,such as RABBITT(the Reconstruction of Attosecond Beating By Interference of Two-photon Transitions),attosecond streaking camera and etcetera.The RABBITT technique uses an HHG(High-Harmonic Generation)pulse together with its fundamental infra-red laser pulse to interact with atoms.And the relative phase of HHG can be obtained by analyzing the special structures in the photoelectron energy spectra.Later,this technique is developed to detect the time delay of photoelectrons emission in attosecond order.Recently researches find that the special structures in photoelectron energy spectra in the RABBITT experiments appear in the two-color ATI(Above-Threshold Ionization)experiments as well,which infers that we may study the dynamic process of photoelectron ionization from these structures.However,the origins of these RABBITT-like structures in the two-color ATI regime are different from those in the HHG experiments.And the studies of these special structures in ATI experiments are usually based on the viewpoint of photon absorption,which is often complicated and non-intuitive.In this thesis,we systematically study the dynamic process of the ionization of noble gas molecules by two-color laser fields from both experimental and theoretical aspects.Based on the semiclassical method,we analyze the RABBITT-like structures appeared in the two-color ATI experiments.Experimentally,we perform the experiments of ionization of Kr atom by two-color laser pulse.The energy spectra of emitted electrons are obtained with COLTRIMS(the COLd Target Recoil-Ion Momentum Spectroscopy).Theoretically,we analyze the oscillation of each peak of electron yield with the relative phase between two color laser fields based on the SFA(Strong Field Approximation)method.And we further give out the analytical expression of the modulation of electron yields in each peak based on analytical derivation.Our work provides important references to the study of dynamic process of electron ionization with two-color laser pulse in the ATI regime in the future.