Extreme-ultraviolet vector-vortex beams from high harmonic generation

Structured light in the short-wavelength regime opens exciting avenues for the study of ultrafast spin and electronic dynamics. Here, we demonstrate theoretically and experimentally the generation of vector-vortex beams (VVB) in the extreme ultraviolet through high-order harmonic generation (HHG). The up-conversion of VVB, which are spatially tailored in their spin and orbital angular momentum, is ruled by the conservation of the topological Pancharatnam charge in HHG. Despite the complex propagation of the driving beam, high-harmonic VVB are robustly generated with smooth propagation properties. Remarkably, we find out that the conversion efficiency of high-harmonic VVB increases with the driving topological charge. Our work opens the possibility to synthesize attosecond helical structures with spatially varying polarization, a unique tool to probe spatiotemporal dynamics in inhomogeneous media or polarization-dependent systems. (C) 2022 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

In this study, we demonstrate the generation of vector-vortex beams (VVB) with specific spin and orbital angular momentum in the extreme ultraviolet through high-order harmonic generation. We find that the conversion efficiency of high-harmonic VVB is related to the topological charge of the driving beam, and they exhibit robust generation and smooth propagation properties. Our work opens up the possibility of synthesizing attosecond helical structures with spatially varying polarization, providing a unique tool to probe spatiotemporal dynamics in inhomogeneous media or polarization-dependent systems.