Quantum path interference in the wavelength dependence of high-harmonic generation

TL;DR

This paper explores how quantum path interference causes rapid fluctuations in high-harmonic generation intensity as a function of wavelength, revealing complex quantum effects in strong-field physics.

Contribution

It uncovers the origin of fine-scale fluctuations in HHG intensity, attributing them to interference among multiple quantum paths with up to five returning orbits.

Findings

Detected strong, rapid fluctuations in HHG intensity with wavelength.

Attributed fluctuations to quantum path interference effects.

Identified up to five returning orbits contributing to the interference.

Abstract

We investigate the dependence of the intensity of radiation due to high-harmonic generation (HHG) as a function of the wavelength of the fundamental driver field. Superimposed on a smooth power-law dependence observed previously we find surprisingly strong and rapid fluctuations on a fine wavelength scale. We identify the origin of these fluctuations in terms of quantum path interferences with up to five returning orbits significantly contributing.