A5032037295- Laser-Matter Interactions and Applications
- Advanced X-ray Imaging Techniques
- Spectroscopy and Quantum Chemical Studies
- Advanced Chemical Physics Studies
- Particle Accelerators and Free-Electron Lasers
- X-ray Spectroscopy and Fluorescence Analysis
- Laser-Plasma Interactions and Diagnostics
- Iron oxide chemistry and applications
- Mass Spectrometry Techniques and Applications
- Advanced Electron Microscopy Techniques and Applications
- Crystallography and Radiation Phenomena
- Advanced Fiber Laser Technologies
- Photosynthetic Processes and Mechanisms
- Photochemistry and Electron Transfer Studies
- Magnetic Properties and Synthesis of Ferrites
- High-pressure geophysics and materials
- Catalytic C–H Functionalization Methods
- Electronic and Structural Properties of Oxides
- Electron and X-Ray Spectroscopy Techniques
- Radical Photochemical Reactions
- Ion-surface interactions and analysis
- Particle accelerators and beam dynamics
- Photorefractive and Nonlinear Optics
- Clay minerals and soil interactions
- Spectroscopy and Laser Applications
Paul Scherrer Institute
2018-2024
École Polytechnique Fédérale de Lausanne
2012-2021
Charles Humbert 8
2017-2020
Photonics (United States)
2020
Center for Biomolecular Nanotechnologies
2015
National Research Council
2015
Imperial College London
2011-2014
Transition metal reactivity toward carbon-hydrogen (C-H) bonds hinges on the interplay of electron donation and withdrawal at center. Manipulating this in a controlled way is difficult because hypothesized metal-alkane charge-transfer interactions are challenging to access experimentally. Using time-resolved x-ray spectroscopy, we track during C-H activation octane by cyclopentadienyl rhodium carbonyl complex. Changes oxidation state as well valence-orbital energies character emerge data...
We report on the full amplitude and phase characterization of high-intensity few-cycle laser pulses generated in a single-stage hollow core fiber system with subsequent compression by ultrabroadband chirped mirrors. use spatially-encoded arrangement (SEA) spectral interferometry for direct electric field reconstruction (SPIDER) filters ancilla generation to characterize sub-4 fs spatial resolution.
We describe a complete technological system at Imperial College London for Attosecond Science studies. The comprises few-cycle, carrier envelope phase stabilized laser source which delivers sub 4 fs pulses to vibration-isolated attosecond vacuum beamline. beamline is used the generation of isolated in extreme ultraviolet (XUV) kilohertz repetition rates through laser-driven high harmonic gas targets. incorporates: interferometers producing pulse sequences pump-probe studies; facility...
The SwissFEL soft X-ray free-electron laser (FEL) beamline Athos will be ready for user operation in 2021. Its design includes a novel layout of alternating magnetic chicanes and short undulator segments. Together with the APPLE X architecture undulators, branch can operated different modes producing FEL beams unique characteristics ranging from attosecond pulse length to high-power modes. Further space has been reserved upgrades including modulators an external seeding better timing...
X-ray free-electron lasers (FELs) are state-of-the-art scientific tools capable to study matter on the scale of atomic processes. Since initial operation FELs more than a decade ago, several facilities with upgraded performance have been put in operation. Here we present first lasing results Athos, soft FEL beamline SwissFEL at Paul Scherrer Institute Switzerland. Athos features an undulator layout based short APPLE-X modules providing full polarisation control, interleaved small magnetic...
A tuneable repetition rate extreme ultraviolet source (Harmonium) for time resolved photoelectron spectroscopy of liquids is presented. High harmonic generation produces 30-110 eV photons, with fluxes ranging from ∼2 × 10(11) photons/s at 36 to 10(8) 100 eV. Four different gratings in a time-preserving grating monochromator provide either high energy resolution (0.2 eV) or temporal (40 fs) between 30 and 110 Laser assisted photoemission was used measure the response system. Vibrational...
A new experimental technique uses an x-ray free-electron laser to reveal charge dynamics within a molecule following removal of electron, paving the way for broader understanding molecular transfer.
The photophysics of ferricyanide in H<sub>2</sub>O, D<sub>2</sub>O and ethylene glycol was studied upon excitation ligand-to-metal charge transfer (LMCT) transitions by combining ultrafast photoelectron spectroscopy (PES) liquids transient vibrational spectroscopy.
Significance The structure–function relationship in central to biology, while the structural dynamics are driven by electronic changes. Doming of ferrous heme proteins, which is respiratory function hemoglobin, ensues from populating high-spin states. However, for ferric doming was excluded. Here, we show that states populated photoexcited cytochrome c , and present evidence doming. We also conclude photo- or thermally activated occurs a wide variety calling deeper understanding its role...
We demonstrate the generation of high-energy sub-2-cycle laser pulses generated through hollow core fibre pulse compression. their full characterization with two independent methods. For all-optical in amplitude and spectral phase, we employ spatially encoded arrangement phase interferometry for direct electric-field reconstruction using spectrally filtered ancilla beams to characterize sub-4-fs spatial resolution. field-sensitive characterization, generate isolated attosecond around 93 eV....
We present a technique for frequency-resolved wavefront characterization of high harmonics based on lateral shearing interferometry. Tilted replicas the driving laser pulse are produced by Mach–Zehnder interferometer, producing separate focii in target. The interference resulting flat-field extreme ultraviolet spectrometer yields spatial phase derivative. A comprehensive set profiles, resolved harmonic order, validate and reveal interplay single-atom macroscopic effects.
The SwissFEL Aramis beamline, covering the photon energies between 1.77 keV and 12.7 keV, features a suite of online diagnostics tools to help both users FEL operators in analysing data optimizing experimental beamline performance. Scientists will be able obtain information about flux, spectrum, position, pulse length, arrival time jitter versus laser for every pulse, with further beam shape size available through use destructive screens. This manuscript is an overview at presents their...
Recent nanomedical applications have again highlighted the significance of silica surface chemistry in solution. Here, we report situ electronic structure measurements at silica–aqueous interface as a function pH for nanoparticles (NPs) 7, 12, and 22 nm using liquid microjet combination with synchrotron radiation. The Si K-edge X-ray absorption near-edge spectroscopy (XANES) spectra reveal change shape 1s → t2 (Si 2p-3s) brought about by changes silanol protonation state NPs result solution...
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 system covering a large wavelength range can be used to generate specific non-equilibrium states, whose subsequent temporal evolution probed by selective scattering techniques 2–12 keV. For that purpose, beamline equipped with elements which tailor beam size energy, as well pulse-to-pulse...
We present a simple electron time of flight spectrometer for resolved photoelectron spectroscopy liquid samples using vacuum ultraviolet (VUV) source produced by high-harmonic generation. The field free coupled with the time-preserving monochromator VUV at Artemis facility Rutherford Appleton Laboratory achieves an energy resolution 0.65 eV 40 sub 100 fs temporal resolution. A key feature design is differentially pumped drift tube allowing microliquid jet to be aligned and started ambient...
The laser-assisted photoelectric effect from liquid surfaces is reported for the first time. Photoelectrons generated by 35.6 eV radiation a microjet of water under vacuum are dressed with ℏω=1.55 laser field. subsequent redistribution photoelectron energies consists in appearance sidebands shifted equivalent to ℏω, 2ℏω, and 3ℏω. response has been modeled third order combined energy-resolved measurements. This result opens possibility investigate dynamics at solutions provide information...
X-ray free-electron lasers (FELs) are modern research tools with applications in multiple scientific fields. Standard x-ray FEL pulses produced by the self-amplified spontaneous emission (SASE) mechanism. SASE-FEL have high power, short duration, and excellent transverse coherence but exhibit poor temporal power spectral profiles consisting of randomly distributed spikes. Here, we present demonstration two modes that enhance radiation: mode-coupled high-brightness SASE. Both schemes based on...
Tailoring the properties of correlated oxides is accomplished by chemical doping, pressure, temperature or magnetic field. Photoexcitation a valid alternative to reach out-of-equilibrium states otherwise inaccessible. Here, we quantitatively estimate coupling between lattice distortion and charge-transfer excitation in (La$_2$CuO$_{4+\delta}$). We photoinduce coherent La ion vibration monitor response optical constants broad energy range, providing quantitative information on electron-phonon...
We demonstrate the generation of coherent soft x-ray free-electron laser (FEL) pulses with a duration below 1 fs using nonlinear compression low-charge electron beam (10 pC). The approach is simple, and it does not require any special hardware, so can be readily implemented at FEL facility. present temporal spectral diagnostics confirming production single-spike sub-femtosecond for photon energies 642 1111 eV. Our work will important ultrafast applications requiring x-rays.
We present a compact passively phase-stabilized ultra-broadband 2D Fourier transform setup. A gas (argon)-filled hollow core fiber pumped by an amplified Ti:Al2O3 laser is used as light source providing spectral range spanning from 420 to 900 nm. Sub-10-fs pulses were obtained using deformable mirror-based pulse shaper. probe the nonlinear response of Rhodamine 101 90 nm bandwidth and resolve vibrational coherences 150 fs period in ground state.