arXiv subjects

R. Weissenbilder

Publications and source records attributed to R. Weissenbilder.

3 recordsLinked to original sources

arXiv2026

Photoelectron interferometry with spectrally shaped polychromatic infrared pulses

Laser-assisted photoelectron interferometry is a cornerstone of attosecond science, first used to characterize attosecond pulse trains and later to study photoionization dynamics. Extending this method to spectrally shaped polychromatic infrared probe fields enables encoding of information across multiple interferometric pathways within the photoelectron spectrum. Here, we experimentally demonstrate laser-assisted photoelectron interferometry using a spectrally shaped polychromatic infrared probe field composed of five distinct spectral components forming a Golomb ruler in the frequency domain. The measured interferograms exhibit multiple beating frequencies that agree with theoretical calculations, demonstrating the simultaneous encoding of multiple laser-assisted quantum beats in a single measurement. A quantitative analysis of the beating amplitudes shows that the strongly modulated temporal profile of the polychromatic probe introduces intensity- and delay-dependent distortions of the quantum beats that cannot be explained by second-order perturbation theory. These results establish the conditions required for the quantitative interpretation of polychromatic photoelectron interferometry and highlight the opportunities offered by spectro-temporal engineering of the probe field for future developments in attosecond science.

physics.atom-ph↗

arXiv2025

Subcycle phase matching effects in short attosecond pulse trains

Attosecond pulses produced by High-order Harmonic Generation (HHG) in gases driven by intense laser fields have become a cornerstone technique for probing ultrafast electronic motion in matter. These applications require a good knowledge of the temporal and spectral properties of the emitted radiation. In this work, we generate a train of two to three attosecond pulses that we characterize using two-color laser-assisted photoionization. \textcolor{black}{An unexpected spectral behavior, with more pulses at high energies than at low energies, is observed when the carrier-to-envelope phase of the laser field is changed by 90$^\circ$.} HHG simulations indicate that the time-dependent phase matching of the harmonics contributes in a non-trivial way to the structure of the pulse train. Two-color laser-assisted photoionization enables us to unravel the dynamical influence of subcycle phase matching on the spectral properties of the attosecond pulse train, going beyond the predictions of the response of a single atom to a strong laser field.

physics.atom-ph↗

arXiv2022

Efficient generation of high-order harmonics in gases

High-order harmonic generation (HHG) in gases leads to short-pulse extreme ultraviolet (XUV) radiation useful in a number of applications, for example, attosecond science and nanoscale imaging. However, this process depends on many parameters and there is still no consensus on how to choose the target geometry to optimize the source efficiency. Here, we review the physics of HHG with emphasis on the macroscopic aspects of the nonlinear interaction. We analyze the influence of medium length, pressure, position of the medium and intensity of the driving laser on the HHG conversion efficiency (CE), using both numerical modelling and analytical expressions. We find that efficient high-order harmonic generation can be realized over a large range of pressures and medium lengths, if these follow a certain hyperbolic equation. The spatial and temporal properties of the generated radiation are, however, strongly dependent on the choice of pressure and medium length. Our results explain the large versatility in gas target design for efficient HHG and provide design guidance for future high-flux XUV sources.

physics.optics↗