Semiclassical two-step model for strong-field ionization

TL;DR

This paper introduces a semiclassical two-step model for strong-field ionization that accurately reproduces quantum interference effects and electron distributions, providing a computationally efficient alternative to full quantum simulations.

Contribution

The model incorporates path interferences beyond perturbation theory using a semiclassical phase approximation, improving agreement with quantum results in strong-field ionization.

Findings

Accurately reproduces quantum interference patterns

Matches quantum energy and angular distributions

Provides good quantitative agreement with Schrödinger equation solutions

Abstract

We present a semiclassical two-step model for strong-field ionization that accounts for path interferences of tunnel-ionized electrons in the ionic potential beyond perturbation theory. Within the framework of a classical trajectory Monte-Carlo representation of the phase-space dynamics, the model employs the semiclassical approximation to the phase of the full quantum propagator in the exit channel. By comparison with the exact numerical solution of the time-dependent Schr\"odinger equation for strong-field ionization of hydrogen, we show that for suitable choices of the momentum distribution after the first tunneling step, the model yields good quantitative agreement with the full quantum simulation. The two-dimensional photoelectron momentum distributions, the energy spectra, and the angular distributions are found to be in good agreement with the corresponding quantum results. Specifically, the model quantitatively reproduces the fan-like interference patterns in the low-energy part of the two-dimensional momentum distributions as well as the modulations in the photoelectron angular distributions.