High-order harmonic generation from diatomic molecules in elliptically polarized driving fields: a generalized interference condition

TL;DR

This paper develops a generalized interference condition for high-order harmonic generation in diatomic molecules under elliptically polarized fields, revealing how ellipticity affects interference patterns and minima.

Contribution

It introduces a new interference condition that accounts for ellipticity, s-p mixing, and orbital symmetry, extending previous models for linearly polarized fields.

Findings

Ellipticity causes a dynamic shift in interference maxima and minima.

Increasing ellipticity leads to blurring and splitting of interference minima.

The model is validated with results for H2 and Ar2 molecules.

Abstract

We investigate the influence of intense, elliptically polarized driving fields on high-order harmonic spectra from aligned diatomic molecules. We derive a generalized two-center interference condition for elliptically polarized fields, which accounts for s-p mixing and the orbital symmetry, within the strong-field and the single-active electron approximation. We show that the non-vanishing ellipticity introduces an effective dynamic shift in the angle for which the two-center interference maxima and minima occur, with regard to the existing condition for linearly polarized fields. This shift depends on the ratio between the field-dressed momentum components of the returning electron parallel and perpendicular to the major ellipticity axis along each possible orbit. Because of this dependence, we find that there will be a blurring in the two-center interference minima, and that increasing ellipticity leads to splitting in such patterns. These features are investigated in detail for H2 and Ar2.