A5089437915- X-ray Spectroscopy and Fluorescence Analysis
- Advanced X-ray Imaging Techniques
- Particle Accelerators and Free-Electron Lasers
- Metal-Catalyzed Oxygenation Mechanisms
- Advanced Fiber Laser Technologies
- Laser-Matter Interactions and Applications
- Crystallography and Radiation Phenomena
- Optical Network Technologies
- Spectroscopy and Quantum Chemical Studies
- Laser Design and Applications
- Ion-surface interactions and analysis
- Semiconductor Lasers and Optical Devices
- Electron Spin Resonance Studies
- High-pressure geophysics and materials
- Photonic and Optical Devices
- Particle accelerators and beam dynamics
- Magnetism in coordination complexes
- Atomic and Subatomic Physics Research
- Photochemistry and Electron Transfer Studies
- Advanced Frequency and Time Standards
- Diamond and Carbon-based Materials Research
- Electron and X-Ray Spectroscopy Techniques
- Advanced Chemical Physics Studies
- Laser-Plasma Interactions and Diagnostics
- Medical Imaging Techniques and Applications
Paul Scherrer Institute
2006-2021
University of Kassel
2017
École Polytechnique Fédérale de Lausanne
2005-2009
Swiss Light Source
2007-2009
Lawrence Berkeley National Laboratory
2008
University of Lausanne
2003-2004
European Synchrotron Radiation Facility
2002-2003
Alcatel Lucent (Germany)
1997-2002
X-ray absorption spectroscopy is a powerful probe of molecular structure, but it has previously been too slow to track the earliest dynamics after photoexcitation. We investigated ultrafast formation lowest quintet state aqueous iron(II) tris(bipyridine) upon excitation singlet metal-to-ligand-charge-transfer (1MLCT) by femtosecond optical pump/x-ray techniques based on x-ray near-edge structure (XANES). By recording intensity characteristic XANES feature as function laser time delay, we...
The SwissFEL X-ray Free Electron Laser (XFEL) facility started construction at the Paul Scherrer Institute (Villigen, Switzerland) in 2013 and will be ready to accept its first users 2018 on Aramis hard branch. In following sections we summarize various aspects of project, including design soft branches accelerator, results performance simulations, details photon beamlines experimental stations, our commissioning results.
Structural changes of the iron(II)-tris-bipyridine ([Fe(II)(bpy)(3)](2+)) complex induced by ultrashort pulse excitation and population its short-lived (< or =0.6 ns) quintet high spin state have been detected picosecond x-ray absorption spectroscopy. The structural relaxation from to low was followed over entire lifetime excited state. A combined analysis x-ray-absorption near-edge structure extended fine spectroscopy features delivers an Fe-N bond elongation 0.2 in compared singlet ground
We employ grazing-incidence femtosecond x-ray diffraction to characterize the coherent, laser-induced lattice motion of a bismuth crystal as function depth from surface with temporal resolution 193+/-8 fs. The data show direct consequences on carrier diffusion and electron-hole interaction, allowing us estimate an effective rate D=2.3+/-0.3 cm(2)/s for highly excited carriers interaction time 260+/-20
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...
The SwissFEL Injector Test Facility operated at the Paul Scherrer Institute between 2010 and 2014, serving as a pilot plant testbed for development realization of SwissFEL, X-ray Free-Electron Laser facility under construction same institute. test consisted laser-driven rf electron gun followed by an S-band booster linac, magnetic bunch compression chicane diagnostic section including transverse deflecting cavity. It delivered bunches up to 200 pC charge 250 MeV beam energy repetition rate...
We present a setup which allows the measurement of time-resolved x-ray absorption spectra with picosecond temporal resolution on liquid samples at Advanced Light Source Lawrence Berkeley National Laboratories. The is limited by pulse width synchrotron source. characterize different sources noise that limit experiment and single-pulse detection scheme.
We report on the observation of solvation shell rearrangement after abstraction electron from aqueous I- in a laser pump/X-ray probe experiment by recording X-ray absorption L1- and L3-edge spectra, 50 ps excitation. The L1-edge spectra clearly identify I0 neutral species excitation suggest substantial amount back-transfer charge solvent species. Both edge point to significant around I0.
A monolithically integrated widely tunable narrow-linewidth light source was realized on an InP-based quantum dot (QD) gain material. The quasi zero-dimensional nature of QDs and the resulting low linewidth enhancement factor enabled standalone distributed feedback (DFB) lasers with intrinsic linewidths as 110 kHz. An device comprising four DFB on-chip micro-heaters, a 3 dB-coupler network, semiconductor optical amplifier (SOA), which covers entire C+ telecom band, exhibits below 200 kHz...
We describe an experimental setup, which measures transient chemical changes of photoexcited solutes in disordered systems via time-resolved X-ray Absorption Spectroscopy (XAS) with picosecond temporal resolution. The setup combines a femtosecond amplified laser x-ray pulses at beamline 5.3.1 the Advanced Light Source Berkeley, USA. New results on XAS used for probing both electronic and geometric modifications tris-(2,2'-bipyridine) ruthenium (II), [RuII(bpy)3]2+ water solution are presented.
The authors experimentally demonstrate robust asynchronous optical multiuser access using spectrally encoded broadband sources. In a system experiment, four transmitters operate simultaneously at 155.52 and 77.76 Mbit/s in an optically amplified tree network with standard singlemode fibres. A BER of 10–10 is achieved without error floor tunable balanced receiver. This technique suitable for application arbitrary fibre architectures.
Femtosecond laser-induced strain waves in InSb are studied by means of time-resolved x-ray diffraction. The temporal evolution the measured diffracted intensity reveals that lattice dynamics depends on time scale energy transfer from excited carriers to lattice. A framework accounts for this energy-transfer (lattice heating time) is presented and applied model fluence dependence transient diffraction data. In initial wave crucially time, which decreases with increasing fluence.
A rod of single crystalline silicon has been subjected to high-power nanosecond laser pulses inducing ultrasonic and shock waves traveling into the bulk material. Stroboscopic time-resolved high-energy x-ray diffraction measurements were carried out in situ probe for strain states sample. First, a supersonic front is observed which moves faster than longitudinal acoustic phonons. Following front, much slower bunch travels along crystal. The records obtained different configurations reflect...
We describe an advanced setup for time‐resolved x‐ray absorption fine structure (XAFS) Spectroscopy with picosecond temporal resolution. It combines intense femtosecond laser source synchronized to the pulses delivered into microXAS beamline of Swiss Light Source (SLS). The is applied measure short‐lived high‐spin geometric photoexcited aqueous Fe(bpy)3 at room temperature.
A new X-ray chopper system based on air-bearing technology was developed in a joint project between the Paul Scherrer Institut and DESY. The wheel of 150 mm diameter has slit width 50 µm, which corresponds to an opening time 230 ns at 30 000 r min −1 . is equipped with either one or two slits slightly different radii, resulting repetition frequencies 500 1000 Hz. To reduce air friction operated reduced-pressure environment. controlled by specially phase lock loop controller, synchronized...
Time-resolved high-energy x-ray diffraction measurements were used to examine laser shock-induced changes in cadmium sulfide single crystals compressed along the c axis near 1.5 and 3.5 GPa. Macroscopic compression under different loading conditions was monitored through evolution of (004) Bragg reflection Laue geometry. In low-stress experiments, elastic response sample evidenced by reversible intensity profiles, while a plastic behavior observed high-stress experiments. A residual is...
The introduction of pump-probe techniques to the field x-ray absorption spectroscopy (XAS) has allowed monitoring both structural and electronic dynamics disordered systems in condensed phase with unprecedented accuracy, time space. We present results on electronically excited high-spin state structure an Fe(II) molecular species, [FeII(bpy)3]2+, aqueous solution, resolving Fe-N bond distance elongation as 0.2 Å. In addition analysis technique using reduced χ2 goodness fit between FEFF EXAFS...
With a femtosecond laser pulse we rapidly ionize potassium atoms $({\mathrm{K}}^{0})$ in the gas phase, generating ions $({\mathrm{K}}^{+})$, and monitor altered energy-level scheme with subsequent hard x-ray pulse. Removal of $4s$ valence electron increases binding energies both $1s$ core levels, induces an ultrafast change $1s\text{\ensuremath{-}}4p$ transition energy by about $2.8\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$. We simultaneously observe 50% increase oscillator strength...
The transmission of 32 channels at 40 Gbit/s is demonstrated over 3 × 100 km TeraLight™ fibre. result was obtained with full ETDM terminal equipment and hybrid Raman/erbium amplifiers.
Abstract SwissFEL is a compact, high-brilliance, soft and hard X-ray free electron laser (FEL) facility that started user operation in 2019. The composed of two parallel beam lines seeded by common linear accelerator (LINAC), two-bunch photo-injector. For the injector, an innovative dual-photocathode scheme has been developed based on state-of-the-art ytterbium femtosecond systems. In this paper, we describe performance photocathode drive lasers (PCDLs), pulse-shaping capabilities as well...