Tunable orbital angular momentum in high-harmonic generation

TL;DR

This paper demonstrates the generation of extreme-ultraviolet optical vortices with controllable orbital angular momentum, enabling new research avenues in high-energy optics and material science.

Contribution

It introduces a method to produce femtosecond EUV vortices with tunable OAM, advancing understanding of angular momentum conservation and control in nonlinear light-matter interactions.

Findings

Generation of EUV optical vortices with femtosecond duration

Controllable orbital angular momentum in high-harmonic generation

Potential to test novel optical phenomena like OAM-induced dichroism

Abstract

Optical vortices are currently one of the most intensively studied topics in optics. These light beams, which carry orbital angular momentum (OAM), have been successfully utilized in the visible and infrared in a wide variety of applications. Moving to shorter wavelengths may open up completely new research directions in the areas of optical physics and material characterization. Here, we report on the generation of extreme-ultraviolet optical vortices with femtosecond duration carrying a controllable amount of OAM. From a basic physics viewpoint, our results help to resolve key questions such as the conservation of angular momentum in highly-nonlinear light-matter interactions, and the disentanglement and independent control of the intrinsic and extrinsic components of the photon's angular momentum at short-wavelengths. The methods developed here will allow testing some of the recently proposed concepts such as OAM-induced dichroism, magnetic switching in organic molecules, and violation of dipolar selection rules in atoms.