Attosecond Interference Induced by Coulomb-Field-Driven Transverse Backward-Scattering Electron Wave-Packets

TL;DR

This paper reveals a new Coulomb-field-driven transverse backward-scattering interference in photoelectron momentum distributions, enabling ultrafast electron dynamics imaging in atoms and molecules with attosecond precision.

Contribution

It introduces a novel interference structure caused by transverse backward-scattering, expanding understanding of electron dynamics beyond conventional rescattering models.

Findings

Identifies a universal transverse interference pattern in photoelectron distributions.

Links the interference to electrons ionized within 200 attoseconds of the laser field crest.

Demonstrates potential for ultrafast electron dynamics measurement.

Abstract

A novel and universal interference structure is found in the photoelectron momentum distribution of atoms in intense infrared laser field. Theoretical analysis shows that this structure can be attributed to a new form of Coulomb-field-driven backward-scattering of photoelectrons in the direction perpendicular to the laser field, in contrast to the conventional rescattering along the laser polarization direction. This transverse backward-scattering process is closely related to a family of photoelectrons initially ionized within a time interval of less than 200 attosecond around the crest of the laser electric field. Those electrons, acquiring near-zero return energy in the laser field, will be pulled back solely by the ionic Coulomb field and backscattered in the transverse direction. Moreover, this rescattering process mainly occurs at the first or the second return times, giving rise to different phases of the photoelectrons. The interference between these photoelectrons leads to unique curved interference fringes which are observable for most current intense field experiments, opening a new way to record the electron dynamics in atoms and molecules on a time scale much shorter than an optical cycle.