Analysis of two-dimensional high-energy photoelectron momentum distributions in single ionization of atoms by intense laser pulses

TL;DR

This paper investigates high-energy photoelectron momentum distributions in atomic ionization under intense laser pulses, using the second-order strong field approximation validated against Schrödinger equation solutions, revealing insights into electron rescattering dynamics.

Contribution

The study introduces the SFA2 model for analyzing 2D electron momentum distributions, including rescattering effects, and compares it with TDSE results for validation.

Findings

Back rescattered ridge yield linked to elastic backward scattering.

Electron wave packets depend on laser intensity and pulse duration.

Long pulse analysis reveals multiple return wave packet characteristics.

Abstract

We analyzed the two-dimensional (2D) electron momentum distributions of high-energy photoelectrons of atoms in an intense laser field using the second-order strong field approximation (SFA2). The SFA2 accounts for the rescattering of the returning electron with the target ion to first order and its validity is established by comparing with results obtained by solving the time-dependent Schr\"{o}dinger equation (TDSE) for short pulses. By analyzing the SFA2 theory, we confirmed that the yield along the back rescattered ridge (BRR) in the 2D momentum spectra can be interpreted as due to the elastic scattering in the backward directions by the returning electron wave packet. The characteristics of the extracted electron wave packets for different laser parameters are analyzed, including their dependence on the laser intensity and pulse duration. For long pulses we also studied the wave packets from the first and the later returns.