Publications associées à Picosecond dynamics of laser-induced strain in graphite

Influence of ionization and cumulative effects on laser-induced crystallization in multilayer dielectrics

Yves Bellouard, Ruben Ricca, Victor Carle Adrien Boureau

Crystallization of amorphous layers has been demonstrated under various radically different laser-exposure conditions, including continuous wave (cw) and pulsed lasers. Here, we investigate the specific role of ionization in the crystallization of dielectr ...

2024

Femtosecond-laser direct-write photoconductive patterns on tellurite glass

Yves Bellouard, Gözden Torun, Anastasia Romashkina

We report the formation of arbitrary photoconductive patterns made of tellurium (Te) nanocrystals by exposing a tellurite (TeO2-based) glass to femtosecond laser pulses. During this process, Te/TeO2-glass nanocomposite interfaces with photoconductive prope ...

American Physical Society (APS)2024

Numerical Study of the Attosecond Free-Electron Laser Pulse Generation in the Soft X-ray Regime at the SwissFEL

Longdi Zhu

Isolated attosecond pulses from an X-ray free-electron laser are in high demand for attosecond science, which enables the probing of electron dynamics by X-ray nonlinear spectroscopy and single-particle imaging. The aim of this thesis is to simulate attos ...

EPFL2024

Laser-based manufacturing of freeform glass micro-optics through topological transformation

Samuel Youcef Benketaf

Glass has been the material of choice for making optical elements, in large part due to its intrinsic properties: a temperature-dependent viscosity, which enables shaping the material into a broad variety of functional and artistic glassware. Silica glass ...

EPFL2024

A compact approach to higher-resolution resonant inelastic x-ray scattering detection using photoelectrons

Henrik Moodysson Rønnow, Markus Scholz

The detection of inelastically scattered soft x-rays with high energy resolution usually requires large grating spectrometers. Recently, photoelectron spectrometry for analysis of x-rays (PAX) has been rediscovered for modern spectroscopy experiments at sy ...

Iop Publishing Ltd2024

Shaped Laser Pulses for Microsecond Time-Resolved Cryo-EM: Outrunning Crystallization during Flash Melting

Marcel Drabbels, Ulrich Lorenz, Constantin Richard Krüger, Nathan Junior Mowry

Water vitrifies if cooled at rates above 3 × 105 K/s. In contrast, when the resulting amorphous ice is flash heated, crystallization occurs even at a more than 10 times higher heating rate, as we have recently shown. This may present an issue for microseco ...

2024

Photothermal spectroscopy on-chip sensor for the measurement of a PMMA film using a silicon nitride micro-ring resonator and an external cavity quantum cascade laser

Simone Iadanza

Laser-based mid-infrared (mid-IR) photothermal spectroscopy (PTS) represents a selective, fast, and sensitive analytical technique. Recent developments in laser design permits the coverage of wider spectral regions in combination with higher power, enablin ...

Walter De Gruyter Gmbh2024

Subsurface fluorescence time-of-flight imaging using a large-format single-photon avalanche diode sensor for tumor depth assessment

Claudio Bruschini, Edoardo Charbon, Arin Can Ülkü, Yichen Feng

Significance: Fluorescence guidance is used clinically by surgeons to visualize anatomical and/or physiological phenomena in the surgical field that are difficult or impossible to detect by the naked eye. Such phenomena include tissue perfusion or molecula ...

SPIE Society of Photo-optical Instrumentation Engineers2024

Exciton migration in two-dimensional materials

Excitons play an essential role in the optical response of two-dimensional materials. These are bound states showing up in the band gaps of many-body systems and are conceived as quasiparticles formed by an electron and a hole. By performing real-time simu ...

Nature Portfolio2024

On the interaction of femtosecond laser pulses with layered dielectric materials

Ruben Ricca

Materials properties are strictly dependent on their microstructure. The internal symmetries and the disposition of the constituting atoms of a material, which depend on its crystallographic structure, greatly affect its response to mechanical, electromagn ...

EPFL2023

In situ monitoring of femtosecond laser-induced modifications in dielectrics

Olivier Bernard

Over the last decades, the progress made in the generation of laser pulses shorter than a picosecond (10^-12 s) has allowed us to reach extreme optical power intensities exceeding 10^15 W cm^-2. This tremendous power has triggered an abundance of original ...

EPFL2023

All-glass miniature GHz repetition rate femtosecond laser cavity

Yves Bellouard, Antoine Maxime Delgoffe, Sargis Hakobyan, Saood Ibni Nazir

Free-space optics allows for design freedom and control, but miniaturization and manufacturability are limited. Here, we present a method for manufacturing complex miniaturized free-space optical systems that combines contactless femtosecond laser-activate ...

2023

Progress and prospects in nonlinear extreme-ultraviolet and X-ray optics and spectroscopy

Majed Chergui

Free-electron lasers and high-harmonic-generation table-top systems are new sources of extreme-ultraviolet to hard X-ray photons, providing ultrashort pulses that are intense, coherent and tunable. They are enabling a broad range of nonlinear optical and s ...

NATURE PORTFOLIO2023

Formation Mechanism of Elemental Te Produced in Tellurite Glass Systems by Femtosecond Laser Irradiation

Yves Bellouard, Gözden Torun

The formation of elemental trigonal tellurium (t-Te) on tellurite glass surfaces exposed to femtosecond laser pulses is discussed. Specifically, the underlying elemental crystallization phenomenon is investigated by altering laser parameters in common tell ...

Wiley2023

Femtosecond laser-induced modifications and self-organization in complex glass systems

Gözden Torun

Ultrashort laser pulses, i.e., pulses emitted shorter than a picosecond, can tailor material properties by introducing permanent modifications locally in three dimensions. Remarkably, under a certain exposure condition, these modifications are accompanied ...

EPFL2023

Terahertz waveform synthesis in integrated thin-film lithium niobate platform

Jérôme Faist, Ileana-Cristina Benea-Chelmus, Francesca Fabiana Settembrini

Bridging the "terahertz gap" relies upon synthesizing arbitrary waveforms in the terahertz domain enabling applications that require both narrow band sources for sensing and few-cycle drives for classical and quantum objects. However, realization of custom ...

Nature Portfolio2023

In Situ and Time-Resolved Transmission Electron Microscopy of Nanoscale Processes

Chengcheng Yan

Observing the fast dynamics of nanoscale systems is crucial in order to understand and ultimately control their behavior. Characterizing these dynamic processes requires techniques with atomic spatial resolution and a temporal resolution that matches the t ...

EPFL2023

Two statistical regimes in the transition to filamentation

Debbie Eeltink

We experimentally investigate fluctuations in the spectrum of ultrashort laser pulses propagating in air, close to the critical power for filamentation. Increasing the laser peak power broadens the spectrum while the beam approaches the filamentation regim ...

Optica Publishing Group2023

NMR Crystallography in the Big Data Era: New Methods and Applications Powered by Machine Learning

Manuel Cordova

Structure determination of materials is key to understanding their physical properties. While single-crystal X-ray diffraction is the gold standard for structures displaying long-range order, many materials of interest are polycrystalline and/or disordered ...

EPFL2023

Charge Dynamics Electron Microscopy Nanoscale Imaging of Femtosecond Plasma Dynamics

Thomas La Grange, Fabrizio Carbone, Luca Piazza, Ivan Madan, Tom Theodorus Antonius Lummen, Gabriele Berruto, Giovanni Maria Vanacore, Francesco Barantani, Ido Kaminer, Simone Gargiulo

Understanding and actively controlling the spatiotemporal dynamics of nonequilibrium electron clouds is fundamental for the design of light and electron sources, high power electronic devices, and plasma-based applications. However, electron clouds evolve ...

AMER CHEMICAL SOC2023