Publications related to Femtochemistry

Experimental demonstration of attosecond pump-probe spectroscopy with an X-ray free-electron laser

Christoph Bostedt, Zhaoheng Guo, Xiang Li, Jun Wang, Siqi Li, Zhen Zhang

Pump-probe experiments with subfemtosecond resolution are the key to understanding electronic dynamics in quantum systems. Here we demonstrate the generation and control of subfemtosecond pulse pairs from a two-colour X-ray free-electron laser. By measurin ...

Nature Publishing Group2024

Investigating Non-equilibrium Physics in Wide Bandgap Semiconductors and Quantum Materials via Ultrafast Spectroscopy

Hui-Yuan Chen

This thesis uses femtosecond laser spectroscopy in studying strong correlation in condensed matters that are pertinent to future technology: a wide bandgap perovskite and a quantum material, with the employment of ultrafast time-resolved spectroscopy in th ...

EPFL2024

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

Ultrafast Electron Microscopy of Nanoscale Charge Dynamics in Semiconductors

Fabrizio Carbone, Ivan Madan, Giovanni Maria Vanacore, Ido Kaminer, Simone Gargiulo, Francesco Barantani, Kangpeng Wang

The ultrafast dynamics of charge carriers in solids plays a pivotal role in emerging optoelectronics, photonics, energy harvesting, and quantum technology applications. However, the investigation and direct visualization of such nonequilibrium phenomena re ...

AMER CHEMICAL SOC2023

Terahertz waveform synthesis in integrated thin-film lithium niobate platform

Ileana-Cristina Benea-Chelmus, Jérôme Faist, 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

Tunable pump compression and fast modulation for pulsed THz generation

Ileana-Cristina Benea-Chelmus, Alessandro Tomasino, Yazan Lampert Almahmoud, Shima Rajabali

We demonstrate tunable dispersion compensation of femtosecond pulses at telecom wavelengths for broadband Terahertz generation in 7.5-meter fiber link using a Silicon prism pair. The prism pair enhances the amplitude of the THz E-field in InGaAs photocondu ...

IEEE2023

Analytics at the nanometer and nanosecond scales by short electron pulses in an electron microscope

Thomas La Grange

Chemical reactions and phase transformations in nanometer-size objects may happen at very short timescales, so conventional characterization tools are not applicable. A new technique combining high spatial and temporal resolution is ultrafast (or dynamic) ...

SPRINGER2022

Optically Triggered Neel Vector Manipulation of a Metallic Antiferromagnet Mn2Au under Strain

Alexey Sapozhnik

The absence of stray fields, their insensitivity to external magnetic fields, and ultrafast dynamics make antiferromagnets promising candidates for active elements in spintronic devices. Here, we demonstrate manipulation of the Neel vector in the metallic ...

AMER CHEMICAL SOC2022

Gain-switched semiconductor laser driven soliton microcombs

Tobias Kippenberg, Junqiu Liu, Erwan Guillaume Albert Lucas, Wenle Weng, Jijun He

Dissipative Kerr soliton generation using self-injection-locked III-V lasers has enabled fully integrated hybrid microcombs that operate in turnkey mode and can access microwave repetition rates. Yet, continuous-wave-driven soliton microcombs exhibit low e ...

Nature Research2021

Helimagnons and Skyrmion Dynamics in Cu2OSeO3 and Fe/Gd Multilayers Explored by Brillouin Light Scattering and X-ray Microscopy

Ping Che

Spin dynamics in skyrmion hosting materials provide novel functionality in magnonics because of the formation of a novel magnon band structure and the nanoscale sizes of magnetic skyrmions. In this thesis, we explore the spin dynamics in the chiral magnet ...

EPFL2021

Relation between Inner Structural Dynamics and Ion Dynamics of Laser-Heated Nanoparticles

Christoph Bostedt

When a nanoparticle is irradiated by an intense laser pulse, it turns into a nanoplasma, a transition that is accompanied by many interesting nonequilibrium dynamics. So far, most experiments on nanoplasmas use ion measurements, reflecting the outside dyna ...

American Physical Society2021

Broadband Quasi-Phase-Matching in All-Optically Poled Stoichiometric Silicon Nitride Waveguides

Camille Sophie Brès, Boris Zabelich, Edgars Nitiss

We show how broadband (>30nm) quasi-phase matching in all-optically poled Si3N4 waveguides provides a platform for efficient sum-frequency generation, and for femtosecond pulse processing such as fcEo detection without the need for group velocity engineeri ...

IEEE2020

Fundamentals and perspectives of ultrafast photoferroic recording

Anna Pogrebna

The ability to switch ferroics (ferro-, ferri-, antiferromagnets, ferroelectrics, multiferroics) between two stable bit states is one of the keystones of modern data storage technology. Due to many new ideas, originating from fundamental research during th ...

2020

Peculiarities of second harmonic generation with chirped femtosecond pulses at high conversion efficiency

Pierre-Marc Jean Marie Dansette

Frequency doubling of an infrared laser radiation in non-linear optical crystals is a widely used technique to obtain light in the visible range. The second harmonic generation process is influenced by several well-known parameters. In this article we stud ...

ELSEVIER2020

Ultra-broadband time-resolved THz spectroscopy of perovskites and nanomaterials

Andrés Burgos Caminal

The fundamental study of charge carrier dynamics has been shown to be of great interest for optoelectronics, paving the way forward for future developments. Often, some of the key processes that determine the photophysics of a material occur on very short ...

EPFL2020

Attosecond transient absorption spooktroscopy: a ghost imaging approach to ultrafast absorption spectroscopy

Christoph Bostedt, Zhaoheng Guo, Jonas Knurr, Andre Al Haddad, Siqi Li

The recent demonstration of isolated attosecond pulses from an X-ray free-electron laser (XFEL) opens the possibility for probing ultrafast electron dynamics at X-ray wavelengths. An established experimental method for probing ultrafast dynamics is X-ray t ...

ROYAL SOC CHEMISTRY2020

Ultrafast nuclear dynamics of the acetylene cation C2H2+ and its impact on the infrared probe pulse induced C-H bond breaking efficiency

Ursula Röthlisberger, Swarnendu Bhattacharyya

The ultrafast nuclear dynamics of the acetylene cation C2H2+ following photoionization of the neutral molecule is investigated using an extreme-ultraviolet pump/infrared probe setup. The observed modulation of the C2H+ fragment ion yield with pump-probe de ...

2019

Excited-state band mapping and momentum-resolved ultrafast population dynamics in In/Si(111) nanowires investigated with XUV-based time- and angle-resolved photoemission spectroscopy

Michele Puppin, Matthias Wolf

We investigate the excited state electronic structure of the model phase transition system In/Si(111) using femtosecond time-and angle-resolved photoemission spectroscopy (trARPES). An extreme ultraviolet 500 kHz laser source at 21.7 eV is utilized both to ...

AMER PHYSICAL SOC2019

Femtosecond Spectroscopy of Au Hot-Electron Injection into TiO2: Evidence for Au/TiO(2 )Plasmon Photocatalysis by Bactericidal Au Ions and Related Phenomena

Juan Kiwi, Sami Rtimi

In the present work, we provide evidence for visible light irradiation of the Au/TiO2 nanoparticles' surface plasmon resonance band (SPR) leading to electron injection from the Au nanoparticles to the conduction band of TiO2. The Au/TiO2 SPR band is shown ...

2019

Upgrade of a low-temperature scanning tunneling microscope for electron-spin resonance

Harald Brune, François Patthey, Nicolas Weiss, Donat Fabian Natterer, Tobias Bilgeri, Patrick Robert Forrester

Electron spin resonance with a scanning tunneling microscope (ESR-STM) combines the high energy resolution of spin resonance spectroscopy with the atomic scale control and spatial resolution of STM. Here we describe the upgrade of a helium-3 STM with a 2D ...

AMER INST PHYSICS2019