Publications by Paul Beaud | EPFL Graph Search

A compact and cost-effective hard X-ray free-electron laser driven by a high-brightness and low-energy electron beam

Lukas Stingelin, Majed Chergui, Paul Beaud, Thomas Schietinger, Christopher Alexander Arrell, Thomas Schmidt, Leonid Rivkin, Christoph Peter Hauri, Giulia Fulvia Mancini, Rasmus Ischebeck, Eugenio Ferrari, Camila Bacellar Cases Da Silveira, Mike Seidel, Paolo Craievich, Sven Reiche

We present the first lasing results of SwissFEL, a hard X-ray free-electron laser (FEL) that recently came into operation at the Paul Scherrer Institute in Switzerland. SwissFEL is a very stable, compact and cost-effective X-ray FEL facility driven by a lo ...

Nature Publishing Group2020

Experimental station Bernina at SwissFEL: condensed matter physics on femtosecond time scales investigated by X-ray diffraction and spectroscopic methods

Paul Beaud, Christopher Alexander Arrell, Christoph Peter Hauri, Giulia Fulvia Mancini, Jochen Rittmann

The Bernina instrument at the SwissFEL Aramis hard X-ray free-electron laser is designed for studying ultrafast phenomena in condensed matter and material science. Ultrashort pulses from an optical laser system covering a large wavelength range can be used ...

International Union of Crystallography (IUCr)2019

Towards X-ray transient grating spectroscopy

Majed Chergui, Paul Beaud, Christian David, Giulia Fulvia Mancini, Erwan Fabrice Koch, Jérémy Raymond Jean Maurice Rouxel

The extension of transient grating spectroscopy to the x-ray regime will create numerous opportunities, ranging from the study of thermal transport in the ballistic regime to charge, spin, and energy transfer processes with atomic spatial and femtosecond t ...

OPTICAL SOC AMER2019

Perspective: Opportunities for ultrafast science at SwissFEL

Majed Chergui, Paul Beaud

We present the main specifications of the newly constructed Swiss Free Electron Laser, SwissFEL, and explore its potential impact on ultrafast science. In light of recent achievements at current X-ray free electron lasers, we discuss the potential territor ...

2018

Watching ultrafast responses of structure and magnetism in condensed matter with momentum-resolved probes

Paul Beaud, Fabrizio Carbone

We present a non-comprehensive review of some representative experimental studies in crystalline condensed matter systems where the effects of intense ultrashort light pulses are probed using x-ray diffraction and photoelectron spectroscopy. On an ultrafas ...

2017

Ultrafast structural dynamics of the orthorhombic distortion in the Fe-pnictide parent compound BaFe2As2

Paul Beaud, Jochen Rittmann

Using femtosecond time-resolved hard x-ray diffraction, we investigate the structural dynamics of the orthorhombic distortion in the Fe-pnictide parent compound BaFe2As2. The orthorhombic distortion analyzed by the transient splitting of the (1 0 3) Bragg ...

Amer Inst Physics2016

Magnetic order dynamics in optically excited multiferroic TbMnO3

Paul Beaud, Christoph Peter Hauri

We performed ultrafast time-resolved near-infrared pump, resonant soft x-ray diffraction probe measurements to investigate the coupling between the photoexcited electronic system and the spin cycloid magnetic order in multiferroic TbMnO3 at low temperature ...

Amer Physical Soc2015

Ultrafast Structural Dynamics of the Fe-Pnictide Parent Compound BaFe2As2

Paul Beaud, Jochen Rittmann

Using femtosecond time-resolved x-ray diffraction we investigate the structural dynamics of the coherently excited A(1g) phonon mode in the Fe-pnictide parent compound BaFe2As2. The fluence dependent intensity oscillations of two specific Bragg reflections ...

American Physical Society2015

Femtosecond X-ray absorption study of electron localization in photoexcited anatase TiO2

Majed Chergui, Paul Beaud, Camelia Borca, Jochen Rittmann, Mahsa Silatani, Edoardo Baldini, Fabio Giacomo Santomauro, Patric Zimmermann

Transition metal oxides are among the most promising solar materials, whose properties rely on the generation, transport and trapping of charge carriers (electrons and holes). Identifying the latter's dynamics at room temperature requires tools that combin ...

Nature Publishing Group2015

Large-Amplitude Spin Dynamics Driven by a THz Pulse in Resonance with an Electromagnon

Paul Beaud, Christoph Peter Hauri

Multiferroics have attracted strong interest for potential applications where electric fields control magnetic order. The ultimate speed of control via magnetoelectric coupling, however, remains largely unexplored. Here, we report an experiment in which we ...

American Association for the Advancement of Science2014

Coherent Structural Dynamics of a Prototypical Charge-Density-Wave-to-Metal Transition

Paul Beaud

Using femtosecond time-resolved x-ray diffraction, we directly monitor the coherent lattice dynamics through an ultrafast charge-density-wave-to-metal transition in the prototypical Peierls system K0.3MoO3 over a wide range of relevant excitation fluences. ...

American Physical Society2014

Temperature-dependent electron-phonon coupling in La_{2−x}Sr_{x}CuO_{4} probed by femtosecond x-ray diffraction

Majed Chergui, Paul Beaud, Mathieu Julien Gino Cottet, Krunoslav Prsa, Henrik Moodysson Rønnow, Fabrizio Carbone, Kazimierz Conder, Giulia Fulvia Mancini

The strength of the electron-phonon coupling parameter and its evolution throughout a solid's phase diagram often determines phenomena such as superconductivity, charge- and spin-density waves. Its experimental determination relies on the ability to distin ...

Amer Physical Soc2013

Direct observation of non-fully-symmetric coherent optical phonons by femtosecond x-ray diffraction

Paul Beaud

We directly measure by femtosecond time-resolved x-ray diffraction the E-g symmetry coherent phonon excited in bismuth by a strong optical pulse. The magnitude of the E-g mode observed is 0.2 pm peak-to-peak, compared against the 2.7-pm initial displacemen ...

American Physical Society2013

Identification of coherent lattice modulations coupled to charge and orbital order in a manganite

Paul Beaud

We apply grazing-incidence femtosecond x-ray diffraction to investigate the details of the atomic motion connected with a displacively excited coherent optical phonon. We concentrate on the low frequency phonon associated with the charge and orbital order ...

American Physical Society2013

Structural and Magnetic Dynamics of a Laser Induced Phase Transition in FeRh

Paul Beaud

We use time-resolved x-ray diffraction and magneto-optical Kerr effect to study the laser-induced antiferromagnetic to ferromagnetic phase transition in FeRh. The structural response is given by the nucleation of independent ferromagnetic domains (tau(1) s ...

American Physical Society2012

Femtosecond dynamics of the structural transition in mixed valence manganites

Paul Beaud

We investigate the structural response of charge and orbitally ordered (CO/OO) manganites to ultrafast optical excitation using optical reflectivity and x-ray diffraction as a probe. We study a La0.42Ca0.58MnO3 (LCMO) thin film and a La0.25Pr0.375Ca0.375Mn ...

American Physical Society2012

Probing the Transition from Hydrophilic to Hydrophobic Solvation with Atomic Scale Resolution

Majed Chergui, Paul Beaud, Ivano Tavernelli, Amal El Nahhas, Van Thai Pham, Renske Marjan van der Veen, Frederico Alves Lima, Thomas James Penfold

Picosecond and femtosecond X-ray absorption spectroscopy is used to probe the changes of the solvent shell structure upon electron abstraction of aqueous iodide using an ultrashort laser pulse. The transient L-1,L-3 edge EXAFS at 50 ps time delay points to ...

2011

Nonthermal Melting of a Charge Density Wave in TiSe2

Paul Beaud

We use time-resolved optical reflectivity and x-ray diffraction with femtosecond resolution to study the dynamics of the structural order parameter of the charge density wave phase in TiSe2. We find that the energy density required to melt the charge densi ...

American Physical Society2011

Picosecond dynamics of laser-induced strain in graphite

Paul Beaud

We report on the use of grazing-incidence time-resolved x-ray diffraction to investigate the evolution of strain in natural graphite excited by femtosecond-laser pulses in the fluence range of 6-35 mJ/cm(2). Strains corresponding to up to similar to 2.8% c ...

2011

Ultrafast Structural Dynamics in Condensed Matter

Paul Beaud

We review our recent activity in the field of photo-induced structural dynamics in crystalline solids studied using femtosecond X-ray diffraction techniques. ...

2011