A5021708705- Laser-Matter Interactions and Applications
- Advanced X-ray Imaging Techniques
- Particle Accelerators and Free-Electron Lasers
- Advanced Chemical Physics Studies
- Laser-Plasma Interactions and Diagnostics
- Atomic and Molecular Physics
- Spectroscopy and Quantum Chemical Studies
- Quantum, superfluid, helium dynamics
- X-ray Spectroscopy and Fluorescence Analysis
- Laser-induced spectroscopy and plasma
- Advanced Electron Microscopy Techniques and Applications
- Particle accelerators and beam dynamics
- Advanced Fiber Laser Technologies
- Mass Spectrometry Techniques and Applications
- High-pressure geophysics and materials
- Laser Design and Applications
- Spectroscopy and Laser Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Fullerene Chemistry and Applications
- Electron and X-Ray Spectroscopy Techniques
- Atmospheric Ozone and Climate
- Nuclear Physics and Applications
- Crystallography and Radiation Phenomena
- Ion-surface interactions and analysis
- Atomic and Subatomic Physics Research
Hamburg Centre for Ultrafast Imaging
2016-2025
Centre for Sight
2025
Deutsches Elektronen-Synchrotron DESY
2014-2024
Max Planck Institute for the Structure and Dynamics of Matter
2015-2024
Universität Hamburg
1999-2022
Helmut Schmidt University
2022
University of New York in Prague
2022
Charles University
2022
Imperial College London
2022
European X-Ray Free-Electron Laser
2022
We report on the dynamics of ultrafast heating in cryogenic hydrogen initiated by a ≲300 fs, 92 eV free electron laser x-ray burst. The rise scattering amplitude from second pulse probes transition dense molecular to nearly uncorrelated plasmalike structure, indicating an electron-ion equilibration time ∼0.9 ps. agrees with radiation hydrodynamics simulations based conductivity model for partially ionized plasma that is validated two-temperature density-functional theory.
Extreme-ultraviolet to x-ray free-electron lasers (FELs) in operation for scientific applications are up now single-user facilities. While most FELs generate around 100 photon pulses per second, FLASH at DESY can deliver almost two orders of magnitude more this time span due its superconducting accelerator technology. This makes the facility a prime candidate realize next step FELs—dividing electron pulse trains into several FEL lines and delivering users same time. Hence, has been extended...
Abstract The recent development of ultrafast extreme ultraviolet (XUV) coherent light sources bears great potential for a better understanding the structure and dynamics matter. Promising routes are advanced control nonlinear spectroscopy schemes in XUV energy range, yielding unprecedented spatial temporal resolution. However, their implementation has been hampered by experimental challenge generating pulse sequences with precisely controlled timing phase properties. In particular, direct...
We investigate ultrafast (fs) electron dynamics in a liquid hydrogen sample, isochorically and volumetrically heated to moderately coupled plasma state. Thomson scattering measurements using 91.8 eV photons from the free-electron laser Hamburg (FLASH at DESY) show that has been driven nonthermal state with an temperature of 13 ion below 0.1 eV, while density is 2.8x10{20} cm{-3}. For dense plasmas, our experimental data strongly support nonequilibrium kinetics model uses impact ionization...
Femtosecond x-ray laser flashes with power densities of up to 10(14) W/cm(2) at 13.7 nm wavelength were scattered by single xenon clusters in the gas phase. Similar light scattering from atmospheric microparticles, diffraction patterns carry information about optical constants objects. However, high flux induces severe transient changes electronic configuration, resulting a tenfold increase absorption developing nanoplasma. The modification opaqueness can be correlated strong atomic charging...
Initiating the gain process in a free-electron laser (FEL) from an external highly coherent source of radiation is promising way to improve pulse properties such as temporal coherence and synchronization performance time-resolved pump-probe experiments at FEL facilities, but this so-called "seeding" suffers lack adequate sources short wavelengths. We report on first successful seeding wavelength 38.2 nm, resulting GW-level, pulses well significant second harmonic emission 19.1 nm. The seed...
Unraveling and controlling chemical dynamics requires techniques to image structural changes of molecules with femtosecond temporal picometer spatial resolution. Ultrashort-pulse x-ray free-electron lasers have significantly advanced the field by enabling pump-probe schemes. There is an increasing interest in using table-top photon sources enabled high-harmonic generation ultrashort-pulse for such studies. We present a novel source driven 100 kHz fiber laser system, which delivers 1011...
The interaction of intense vacuum-ultraviolet radiation from a free-electron laser with rare gas atoms is investigated. ionization products xenon and argon atomic beams are analyzed time-of-flight mass spectroscopy. At 98 nm wavelength $\ensuremath{\sim}{10}^{13}\text{ }\mathrm{W}/{\mathrm{c}\mathrm{m}}^{2}$ multiple charged ions up to ${\mathrm{X}\mathrm{e}}^{6+}$ (${\mathrm{A}\mathrm{r}}^{4+}$) detected. From the intensity dependence ion yields mechanisms multiphoton processes were...
The ionization and charge separation processes of nanoplasmas created by resonant excitation atomic clusters in intense soft x-ray pulses have been investigated. Through irradiation with femtosecond from the FLASH free electron laser (FEL) at λ = 13.7 nm power densities exceeding 1014 W cm−2 are highly ionized transient states up to 9+. Variation cluster composition pristine doped core–shell systems allows tracking spatial origin fragments yielding insight into nanoplasma dynamics. data give...
The ionization dynamics of Ar and Xe clusters irradiated with intense vacuum ultraviolet light from a free-electron laser is investigated using photoelectron spectroscopy. Clusters comprising between 70 900 atoms were femtosecond pulses at 95 nm wavelength ($\ensuremath{\sim}13\text{ }\text{ }\mathrm{eV}$ photon energy) peak intensity $\ensuremath{\sim}4\ifmmode\times\else\texttimes\fi{}{10}^{12}\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$. A broad thermal distribution emitted electrons maximum...
The disintegration mechanisms for xenon clusters in intense femtosecond soft x-ray pulses from the FLASH free electron laser are investigated. irradiated at a wavelength of λ = 13.7 nm (hν 90.5 eV) and power densities 5 × 1014 W cm−2. During 10 fs pulse Xe transformed into highly excited, multiply charged nanoplasma. Simulating ion kinetic energies an electrostatic model suggests that ions explode off surface due to Coulomb repulsion while inner core expands hydrodynamic expansion. current...
By use of high intensity XUV radiation from the FLASH free-electron laser at DESY, we have created highly excited exotic states matter in solid-density aluminum samples. The is sufficiently to excite an inner-shell electron a large fraction atoms focal region. We show that soft-x-ray emission spectroscopy measurements reveal electronic temperature and density this system immediately after excitation pulse, with detailed calculations structure, based on finite-temperature functional theory,...
Here, we use x-rays to create and probe quantum coherence in the photoionized amino acid glycine. The outgoing photoelectron leaves behind cation a coherent superposition of mechanical eigenstates. Delayed x-ray pulses track induced through resonant absorption that induces Auger decay by emission from sequential double photoionization. Sinusoidal temporal modulation detected signal at early times (0 25 fs) is observed both measurements. Advanced ab initio many-electron simulations allow us...
The response of Ar clusters to intense vacuum-ultraviolet pulses is investigated with photoion spectroscopy. By varying the laser wavelength, initial excitation was either tuned absorption bands surface or bulk atoms clusters. Multiple ionization observed, which leads Coulomb explosion. efficiency resonant 2-photon for and compared that nonresonant process at different intensities. specific electronic structure plays almost no role in explosion dynamics a peak intensity larger than...
We report the creation of solid-density aluminum plasma using free-electron laser (FEL) radiation at $13.5\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ wavelength. Ultrashort pulses were focused on a bulk Al target, yielding an intensity $2\ifmmode\times\else\texttimes\fi{}{10}^{14}\phantom{\rule{0.3em}{0ex}}\mathrm{W}∕{\mathrm{cm}}^{2}$. The emitted from was measured xuv spectrometer. Bremsstrahlung and line ratios yield consistent electron temperatures about...
Femtosecond laser pulses tailored with closed-loop, optimal control feedback were used to excite oscillations in C60 large amplitude by coherent heating of nuclear motion. A characteristic pulse sequence results significant enhancement C2 evaporation, a typical energy loss channel vibrationally hot C60. The separation between subsequent combination complementary two-color pump-probe data and time-dependent density functional theory calculations give direct information on the multielectron...
Highly charged ions are formed in the center of composite clusters by strong free-electron laser pulses and they emit fluorescence on a femtosecond time scale before competing recombination leads to neutralization nanoplasma core. In contrast mass spectrometry that detects remnants interaction, extreme ultraviolet spectral range provides fingerprints transient states high energy density matter. Spectra from consisting xenon core surrounding argon shell show small fraction signal comes...
Abstract Light-phase-sensitive techniques, such as coherent multidimensional spectroscopy, are well-established in a broad spectral range, already spanning from radio-frequencies nuclear magnetic resonance spectroscopy to visible and ultraviolet wavelengths nonlinear optics with table-top lasers. In these cases, the ability tailor phases of electromagnetic waves high precision is essential. Here we achieve phase control extreme-ultraviolet pulses free-electron laser (FEL) on attosecond...
Femtosecond transient soft X-ray absorption spectroscopy (XAS) is a very promising technique that can be employed at free-electron lasers (FELs) to investigate out-of-equilibrium dynamics for material and energy research. Here, dedicated setup X-rays available the Spectroscopy Coherent Scattering (SCS) instrument European Free-Electron Laser (European XFEL) presented. It consists of beam-splitting off-axis zone plate (BOZ) used in transmission create three copies incoming beam, which are...
Vibrational modes of glucose spanning from 900 to 1400 cm −1 in the molecular fingerprint region have been traced by means vibrational sum-frequency generation spectroscopy aqueous solution as a function concentration. The high sensitivity is enabled 200 kHz few-cycle mid-infrared optical parametric chirped-pulse amplifier (OPCPA). OPCPA generates broadband pulses (from 7 11 μ m) centered at 9 m with 114 fs pulse duration, average power 245 mW and energy 1.2 J. achieved performance...
The coupling of electronic and nuclear motion in polyatomic molecules is at the heart attochemistry. molecular properties, transient structures, reaction mechanism these many-body quantum objects are defined on level electrons ions by wave functions their coherent superposition, respectively. In present contribution, we monitor nonadiabatic packet dynamics during charge reconstructing both oscillatory density distribution characteristic time-dependent configuration coordinate from...