Attosecond XUV vortices from high-order harmonic generation

TL;DR

This paper theoretically investigates high-order harmonic generation driven by vortex-carrying infrared fields, revealing the creation of EUV vortex harmonics, their propagation characteristics, and the potential for generating attosecond helical pulses.

Contribution

It demonstrates the generation and propagation of EUV vortex harmonics with high orbital angular momentum and proposes a method to produce attosecond pulses with helical structures.

Findings

EUV harmonic vortices are generated and survive propagation.

Vortices carry high orbital angular momentum proportional to the driving field.

Harmonic vortices are emitted with similar divergence.

Abstract

We present a theoretical study of high-order harmonic generation (HHG) and propagation driven by an infrared field carrying orbital angular momentum (OAM). Our calculations unveil the following relevant phenomena: extreme-ultraviolet harmonic vortices are generated and survive to the propagation effects, vortices transport high-OAM multiple of the corresponding OAM of the driving field and, finally, the different harmonic vortices are emitted with similar divergence. We also show the possibility of combining OAM and HHG phase-locking to produce attosecond pulses with helical pulse structure.