High-order harmonic generation and multi-photon ionization of ethylene in laser fields

TL;DR

This study uses TDLDA to analyze high-order harmonic generation and multi-photon ionization in ethylene under one- and two-color ultrashort laser pulses, revealing spectral features, symmetry breaking, and ionization dynamics.

Contribution

It demonstrates the effects of two-color laser fields on HHG spectra, symmetry breaking, and ionization probabilities in ethylene, providing new insights into HHG mechanisms.

Findings

Obvious plateaus and odd harmonics in one-color HHG spectrum

Breaking of symmetry and even harmonics generation in two-color HHG

Increased ionization probability of higher charge states with two-color fields

Abstract

Applying time-dependent local density approximation (TDLDA), we study the high-order harmonic generation (HHG) of ethylene subjected to the one-color ($\omega=2.72$ eV) and the two-color ($\omega_1=2.72$ eV and $\omega_2=5.44$ eV) ultrashort intense laser pulses. The HHG spectrum of ethylene in the one-color laser field shows the obvious plateaus and odd order harmonics are produced while the two-color laser field can result in the breaking of the symmetry and generation of the even order harmonic. The ionization probabilities are obtained showing the increase of the ionization probability of higher charge state by the two-color laser field. The temporal structures of HHG spectrum of ethylene is explored by means of the time-frequency analysis showing new insights of the HHG mechanisms in the one-color and the two-color laser fields.