Equivalence of RABBITT and Streaking Delays in Attosecond-Time-Resolved Photoemission Spectroscopy at Solid Surfaces

Andreas Gebauer,Benjamin Stadtmüller,Walter Pfeiffer,Walter Enns,Sergej Neb,Martin Aeschlimann

doi:10.3390/app9030592

Abstract

The dynamics of the photoelectric effect in solid-state systems can be investigated via attosecond-time-resolved photoelectron spectroscopy. This article provides a comparison of delay information accessible by the two most important techniques, attosecond streaking spectroscopy and reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) at solid surfaces, respectively. The analysis is based on simulated time-resolved photoemission spectra obtained by solving the time-dependent Schrödinger equation in a single-active-electron approximation. We show a continuous transition from the few-cycle RABBITT regime to the streaking regime as two special cases of laser-assisted photoemission. The absolute delay times obtained by both methods agree with each other, within the uncertainty limits for kinetic energies >10 eV. Moreover, for kinetic energies >10 eV, both streaking delay time and RABBITT delay time coincide with the classical time of flight for an electron propagating from the emitter atom to the bulk-vacuum interface, with only small deviations of less than 4 as due to quantum mechanical interference effects.

Highlights

The availability of attosecond extreme-ultraviolet (EUV) pulses enabled access to electron dynamics on their natural time scales [1,2,3]
We describe all steps of the photoemission process from excitation to detection by the time-dependent Schrödinger equation (TDSE) in one dimension and in a single-active-electron picture
We start our discussion with a short introduction into the generation of single-attosecond pulses and attosecond pulse trains, which are obtained by the high harmonic generationexcited (HHG) process in noble-gas atoms

Summary

Introduction

The availability of attosecond extreme-ultraviolet (EUV) pulses enabled access to electron dynamics on their natural time scales [1,2,3]. Photoionization and photoemission dynamics are studied in various systems, ranging from atoms [5,6,7] and molecules (for a review, see Reference [8]) to condensed matter systems like solid surfaces [9,10,11,12] and nanoparticles [13]. In this context, fundamental questions arise regarding the role and concept of time in quantum mechanics [14,15]. Aspects like inelastic mean free path, or excited state lifetime, respectively [18], electron-hole interaction [16], infrared (IR)

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Conclusion