Broadband large-ellipticity harmonic generation with polar molecule

TL;DR

This paper demonstrates that polar molecules can produce elliptically polarized high harmonics over a broad spectral range, enabling new applications in material and biological detection.

Contribution

It reveals that the asymmetric structure of the molecular orbital causes harmonic ellipticity, offering a novel method for generating large-ellipticity XUV pulses.

Findings

Elliptically polarized harmonics observed across a wide spectral range.

Molecular orbital asymmetry is responsible for harmonic ellipticity.

Potential for enhanced detection techniques in materials and biology.

Abstract

We investigate the polarization properties of high harmonic generation from polar molecules with a linearly polarized field. It is found that elliptically polarized harmonics are observed in a wide spectral range from the plateau to the cutoff. Further analyses show that the nonsymmetric structure of the highest occupied molecular orbital is the origin of ellipticity of the harmonics. The results provide a method for generation of large-ellipticity XUV pulses, which will benefit the application of HHG as a tool of detection in materials and biology science.