Semi-Classical Wavefunction Perspective to High-Harmonic Generation

TL;DR

This paper presents a semi-classical wavefunction model for high harmonic generation that enables a clear separation of ionization, propagation, and recollision contributions in both time and frequency domains, enhancing understanding of HHG processes.

Contribution

The authors introduce a semi-classical wavefunction formalism that provides a new way to factorize and analyze HHG spectra based on natural temporal and trajectory-based decompositions.

Findings

Frequency-domain factorization of HHG yield into ionization, propagation, and recollision contributions.

Derivation of factorization from the dipole signal using a reference system.

Trajectory-based expression of the factorization allowing attribution of spectral features.

Abstract

We introduce a semi-classical wavefunction (SCWF) model for strong-field physics and attosecond science. When applied to high harmonic generation (HHG), this formalism allows one to show that the natural time-domain separation of the contribution of ionization, propagation and recollisions to the HHG process leads to a frequency-domain factorization of the harmonic yield into these same contributions, for any choice of atomic or molecular potential. We first derive the factorization from the natural expression of the dipole signal in the temporal domain by using a reference system, as in the quantitative rescattering (QRS) formalism [J. Phys. B. 43, 122001 (2010)]. Alternatively, we show how the trajectory component of the SCWF can be used to express the factorization, which also allows one to attribute individual contributions to the spectrum to the underlying trajectories.