8 research outputs found
Symphony on strong field approximation
This paper has been prepared by the Symphony collaboration (University of Warsaw, Uniwersytet Jagielloński, DESY/CNR and ICFO) on the occasion of the 25th anniversary of the 'simple man's models' which underlie most of the phenomena that occur when intense ultrashort laser pulses interact with matter. The phenomena in question include high-harmonic generation (HHG), above-threshold ionization (ATI), and non-sequential multielectron ionization (NSMI). 'Simple man's models' provide both an intuitive basis for understanding the numerical solutions of the time-dependent Schrödinger equation and the motivation for the powerful analytic approximations generally known as the strong field approximation (SFA). In this paper we first review the SFA in the form developed by us in the last 25 years. In this approach the SFA is a method to solve the TDSE, in which the non-perturbative interactions are described by including continuum–continuum interactions in a systematic perturbation-like theory. In this review we focus on recent applications of the SFA to HHG, ATI and NSMI from multi-electron atoms and from multi-atom molecules. The main novel part of the presented theory concerns generalizations of the SFA to: (i) time-dependent treatment of two-electron atoms, allowing for studies of an interplay between electron impact ionization and resonant excitation with subsequent ionization; (ii) time-dependent treatment in the single active electron approximation of 'large' molecules and targets which are themselves undergoing dynamics during the HHG or ATI processes. In particular, we formulate the general expressions for the case of arbitrary molecules, combining input from quantum chemistry and quantum dynamics. We formulate also theory of time-dependent separable molecular potentials to model analytically the dynamics of realistic electronic wave packets for molecules in strong laser fields. We dedicate this work to the memory of Bertrand Carré, who passed away in March 2018 at the age of 60
Symphony on strong field approximation
This paper has been prepared by the Symphony collaboration (University of Warsaw,
Uniwersytet Jagielloński, DESY/CNR and ICFO) on the occasion of the 25th anniversary of
the ‘simple man’s models’ which underlie most of the phenomena that occur when intense
ultrashort laser pulses interact with matter. The phenomena in question include high-harmonic
generation (HHG), above-threshold ionization (ATI), and non-sequential multielectron
ionization (NSMI). ‘Simple man’s models’ provide both an intuitive basis for understanding
the numerical solutions of the time-dependent Schrödinger equation and the motivation for the
powerful analytic approximations generally known as the strong field approximation (SFA).
In this paper we first review the SFA in the form developed by us in the last 25 years. In this approach the SFA is a method to solve the TDSE, in which the non-perturbative interactions
are described by including continuum–continuum interactions in a systematic perturbation-like
theory. In this review we focus on recent applications of the SFA to HHG, ATI and NSMI from
multi-electron atoms and from multi-atom molecules. The main novel part of the presented
theory concerns generalizations of the SFA to: (i) time-dependent treatment of two-electron
atoms, allowing for studies of an interplay between electron impact ionization and resonant
excitation with subsequent ionization; (ii) time-dependent treatment in the single active
electron approximation of ‘large’ molecules and targets which are themselves undergoing
dynamics during the HHG or ATI processes. In particular, we formulate the general expressions
for the case of arbitrary molecules, combining input from quantum chemistry and quantum
dynamics. We formulate also theory of time-dependent separable molecular potentials to model
analytically the dynamics of realistic electronic wave packets for molecules in strong laser
fields.Peer Reviewe