Holographic interference in atomic ionization by ultrashort laser pulses

S. D. LÓPEZ; D. G. ARBÓ

Rosario

Workshop; Workshop on Atomic Collisions and Applications; 2019

Comité Organizador AACAP

When an intense short laser pulse interacts with an atom ionizing it, the photoelectron spectra present several structures that can be understood as double slit interferences in the time domain, namely intra- and inter-cycle interferences formed by electrons that emerge from the atom and follow directly to detector [1]. There is another type of structures that requires interference of direct electron trajectories with others that interact with the parent core [2]. In a classical picture, the rescattering trajectories return to the parent ion driven by the laser field and rescatters off to the detector. It is well known that a short range potential is sufficient to understand the rescattering rings at high energy, formed by very hard interaction among electron and ion [3]. Other structures can be explained only when long range coulomb interactions take place. This type of structures can be interpreted as holograms, i.e. the interference pattern between the direct (reference) and the rescattered (signal beam) electrons. In this way, the information of the interaction is encoded in the interference pattern between the reference and the signal [4].In this work we analyze the ionization of atomic hydrogen to characterize the role that the long-range Coulomb interaction plays in the holographic structures. We show in Fig. 1 photoelectron distributions as a function of parallel kz and perpendicular k momentum to polarization axis calculated with the semiclassical two step model (SCTS) model [5] (upper panel) and the numerical solution of the time dependent Schrödinger equation (TDSE) (lower panel). We observe interference patterns resembling a dispersion of an electron wave packet from a potential centered in the origin in both calculations.