Probing scattering phase shifts by attosecond streaking

TL;DR

This paper demonstrates that attosecond streaking time shifts encode spectral phase information related to the Eisenbud-Wigner-Smith delay, with special considerations for Coulomb potentials, enabling phase probing at the single-particle level.

Contribution

It reveals how streaking phase shifts relate to spectral phase delays and provides a classical description for Coulomb interactions in streaking measurements.

Findings

Streaking time shifts contain spectral phase information.

Agreement with EWS delays for short-ranged potentials.

Classical model describes Coulomb and IR field interactions.

Abstract

Attosecond streaking is one of the most fundamental processes in attosecond science allowing for a mapping of temporal (i.e. phase) information on the energy domain. We show that on the single-particle level attosecond streaking time shifts contain spectral phase information associated with the Eisenbud-Wigner-Smith (EWS) time delay, provided the influence of the streaking infrared field is properly accounted for. While the streaking phase shifts for short-ranged potentials agree with the associated EWS delays, Coulomb potentials require special care. We show that the interaction between the outgoing electron and the combined Coulomb and IR laser fields lead to a streaking phase shift that can be described classically.