Quantitative rescattering theory for laser-induced high-energy plateau photoelectron spectra

TL;DR

This paper introduces a comprehensive quantitative rescattering (QRS) theory that accurately models high-energy photoelectron spectra produced by intense laser pulses, enabling extraction of scattering information and potential for ultrafast molecular imaging.

Contribution

The paper develops and validates a QRS model that links photoelectron spectra to elastic scattering cross sections, extending its application from atomic to molecular targets for chemical imaging.

Findings

QRS accurately predicts high-energy photoelectron spectra.

The returning electron wave packets depend mainly on laser parameters.

Experimental spectra can be explained and scattering cross sections extracted.

Abstract

A comprehensive quantitative rescattering (QRS) theory for describing the production of high-energy photoelectrons generated by intense laser pulses is presented. According to the QRS, the momentum distributions of these electrons can be expressed as the product of a returning electron wave packet with the elastic differential cross sections (DCS) between free electrons with the target ion. We show that the returning electron wave packets are determined mostly by the lasers only, and can be obtained from the strong field approximation. The validity of the QRS model is carefully examined by checking against accurate results from the solution of the time-dependent Schr\"odinger equation for atomic targets within the single active electron approximation. We further show that experimental photoelectron spectra for a wide range of laser intensity and wavelength can be explained by the QRS theory, and that the DCS between electrons and target ions can be extracted from experimental photoelectron spectra. By generalizing the QRS theory to molecular targets, we discuss how few-cycle infrared lasers offer a promising tool for dynamic chemical imaging with temporal resolution of a few femtoseconds.