Holographic structures in photoelectron spectra

LÓPEZ, S. D.; ARBÓ, D. G.

BUDAPEST

Conferencia; The International Conference on Many Particle Spectroscopy of Atoms, Molecules, Clusters and Surfaces; 2018

When an intense short laser pulse interactswith an atom ionizing it, the photoelectron spectrapresent several structures that can be understoodas double slit interferences in the time domain,namely intra- and inter-cycle interferences[1]. This type of structures are formed by electronsthat emerge from the atom and follows directlyto detector. There is another type of structuresthat requires interference of former directelectrons with other that interact with the parentcore. In a classical picture, the latter returnsto the parent ion driven by the laser eld andrescatters o to the detector. It is well knownthat a short range potential is sucient to understandthe rescattering rings at high energy,formed by very hard interaction among electronand ion [2]. Other structures can be explainedonly when long range coulombic interactions takeplace. This type of structures can be interpretedas holograms, i.e. the interference pattern betweenthe direct (reference) and the rescattered(signal beam) electrons. In this way, the informationof the interaction is encoded in the interferencepattern between the reference and thesignal [3].In this work we present a theoretical analysisof interferences using a numerical solution of thetime dependent Schrodinger equation (TDSE)and semiclassical approaches, namely, quantumtrajectory monte carlo (QTMC) and the semiclassicaltwo step model (SCTS) [4]. We analyzethe ionization of atomic hydrogen to characterizethe role that the long range Coulomb interactionplays in the holographic stuctures. Particularly,we focus our analysis for very few cycle laserpulses allowing ionization in some parts, to turnon and o dierent kind of interferences. Withsemiclassical approaches we can examinate thetrajectories that lead to dierent nal conditionsand get a deeper understanding of the electronkinematics associated to holographic structures.We show in Figure 1 photoelectron distributionsas function of parallel kz and perpendicularkx momentum to polarization axis calculatedwith SCTS model (upper pannel) and the TDSE(lower pannel). All the magnitudes are in atomicunits. We observe interference patterns resemblinga dispersion of an electron wave packet froma potential centered in the origin in both calculations.Figure 1. Photoelectron momentum distributionfor ionization of atomic hydrogen by a short laserpulse of frequency !=0.0575 a.u. and electriceld amplitude F0=0.05 a.u. calculated within theSCTS model for a single period laser pulse for SCTS(upper gure) and TDSE (lower gure)This work was supported by the by CONICET(PIP100386) and ANPCYT (PICT-2016-0296 and PICT-2016-3029).References[1] Arbo, D. G., Ishikawa, K. L., Schiessl, K., Persson,E., and Burgdorfer, J. Phys. Rev. A (2010),81, 021403[2] Lewenstein, M., Kulander, K. C., Schafer, K. J.,and Bucksbaum, P. H., Phys. Rev. A (1995),51, 1495[3] Huismans, Y., Rouzee, A., Gijsbertsen, A., etal., Science,(2011) 331, 61[4] Shvetsov-Shilovski, N. et al., Phys. Rev. A,(2016), 94, 013415