High-harmonic generation enhanced by dynamical electron correlation

TL;DR

This paper demonstrates that electron correlation significantly enhances high-harmonic generation signals, revealing new resonance features and extended plateaus through all-electron simulations, with implications for understanding multi-electron dynamics in intense laser fields.

Contribution

The study introduces a first-principles 1D model showing how electron correlation enhances HHG, highlighting mechanisms that could apply to real 3D systems.

Findings

Resonance peak far above the plateau observed

Second plateau extended beyond the first cutoff

Electron correlation enhances dication response significantly

Abstract

We theoretically study multielectron effects in high-harmonic generation (HHG), using all-electron first-principles simulations for a one-dimensional (1D) model atom. In addition to usual plateau and cutoff (from a cation in the present case, since the neutral is immediately ionized), we find a prominent resonance peak far above the plateau and a second plateau extended beyond the first cutoff. These features originate from the dication response enhanced by orders of magnitude due to the action of the Coulomb force from the rescattering electron, and, hence, are a clear manifestation of electron correlation. Although the present simulations are done in 1D, the physical mechanism underlying the dramatic enhancement is expected to hold also for three-dimensional real systems. This will provide new possibilities to explore dynamical electron correlation in intense laser fields using HHG, which is usually considered to be of single-electron nature in most cases.