Federico Vismarra


Last Name

Vismarra

First Name

Federico

ORCID

0000-0002-2348-2749

Organisational unit

03888 - Wörner, Hans Jakob / Wörner, Hans Jakob

Filters

2024 - 20254
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Publications 1 - 4 of 4
  • Self-compressed waveform-stable light transients enabling water-window attosecond spectroscopy
    Item type: Journal Article
    Utrio Lanfaloni, Valentina; Vismarra, Federico; Ardali, Emir; et al. (2025)
    Nature Photonics
    The demonstration of soliton self-compression in the terawatt-level regime using large-core hollow capillary fibres and long-wavelength driving pulses has opened new possibilities for tabletop ultrafast spectroscopy experiments. Here we report the creation of phase-stable sub-cycle self-compressed light transients, as well as their field- and phase-resolved optical field sampling. We demonstrate the direct in situ measurement of self-compressed light transients, reaching durations down to 2.5 ± 0.2 fs, which is half of an optical cycle at a centroid wavelength of 1,366 nm, and determine their waveform phase offset. We apply these transients to soft X-ray high-harmonic generation and attosecond X-ray absorption spectroscopy. Attosecond transient absorption spectroscopy at 250 eV demonstrates the utility of the sub-cycle light transients for experiments with ultimate temporal resolution. The advances reported in this work merge the deep sub-cycle temporal resolution offered by self-compressed, phase-characterized light transients and showcase their application for water-window attosecond X-ray absorption spectroscopy, pushing the boundaries of achievable temporal resolution.
  • Dynamic Interference of Chirped Photoelectrons
    Item type: Journal Article
    Vismarra, Federico; Bertolino, Mattias; Appi, Elisa; et al. (2025)
    Physical Review Letters
    Dynamic interference is an elusive strong-field effect where photoelectrons from intense laser pulses interfere in time, forming rich kinetic energy patterns. Here, we present the first experimental demonstration of isolated dynamic interference using a novel two-color scheme: chirped laser-assisted dynamic interference. Isolation was achieved with a crossed-polarization setup combining an extreme ultraviolet harmonic field and an infrared pulse with tailored spectrotemporal properties. Beyond prior works, our approach enables precise control over interfering trajectories, yielding holographic interference patterns and advancing our understanding of strong-field phenomena.
  • Field-resolved measurements of soliton self-compressed single-cycle pulses and their application to water-window high-harmonic generation
    Item type: Journal Article
    Kopp, Tristan; Redaelli, Leonardo; Wiese, Joss; et al. (2025)
    Optica
    Isolated attosecond pulses (IAPs) in the water window are critical for attosecond spectroscopy of chemical and biochemical dynamics. Their creation via high-harmonic generation (HHG) typically demands carrier-envelope phase (CEP) stabilization and complicated pulse compression of the ultrashort HHG driving pulses. This study describes field-resolved measurements of single-cycle pulses obtained through soliton self-compression of short-wave-infrared (1485 nm) femtosecond pulses. Pulse compression down to 1.1 optical cycles, corresponding to a duration of 5.05 fs, is demonstrated for 1.175 mJ pulses with 0.325 mJ within the full width at half-maximum of the pulse. High-harmonic generation in the water window is achieved with these pulses, and its dependence on the pulse compression is studied. It is also shown that IAPs are obtained for nearly any value of the CEP, which demonstrates that single-cycle pulses obtained from soliton self-compression enable the creation of IAPs without the requirement of a stable CEP. The results of this work open the path to attosecond time-resolved measurements in the water window, benefiting from the higher flux obtained with signal pulses (compared to idler pulses) of widely used optical parametric amplifiers.
  • Isolated attosecond pulse generation in a semi-infinite gas cell driven by time-gated phase matching
    Item type: Journal Article
    Vismarra, Federico; Fernández-Galán, Marina; Mocci, Daniele; et al. (2024)
    Light: Science & Applications
    Isolated attosecond pulse (IAP) generation usually involves the use of short-medium gas cells operated at high pressures. In contrast, long-medium schemes at low pressures are commonly perceived as inherently unsuitable for IAP generation due to the nonlinear phenomena that challenge favourable phase-matching conditions. Here we provide clear experimental evidence on the generation of isolated extreme-ultraviolet attosecond pulses in a semi-infinite gas cell, demonstrating the use of extended-medium geometries for effective production of IAPs. To gain a deeper understanding we develop a simulation method for high-order harmonic generation (HHG), which combines nonlinear propagation with macroscopic HHG solving the 3D time-dependent Schrödinger equation at the single-atom level. Our simulations reveal that the nonlinear spatio-temporal reshaping of the driving field, observed in the experiment as a bright plasma channel, acts as a self-regulating mechanism boosting the phase-matching conditions for the generation of IAPs.
Publications 1 - 4 of 4