A5024592281- Laser-Matter Interactions and Applications
- Advanced X-ray Imaging Techniques
- Advanced Fiber Laser Technologies
- Laser-Plasma Interactions and Diagnostics
- Atomic and Molecular Physics
- Laser-induced spectroscopy and plasma
- Photoacoustic and Ultrasonic Imaging
- Laser Design and Applications
- High-pressure geophysics and materials
- Optical Coherence Tomography Applications
- Advanced Electron Microscopy Techniques and Applications
- Advanced Fluorescence Microscopy Techniques
- Photorefractive and Nonlinear Optics
- Digital Holography and Microscopy
- Mass Spectrometry Techniques and Applications
- Spectroscopy and Laser Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Solid State Laser Technologies
- Particle Accelerators and Free-Electron Lasers
- Advanced Chemical Physics Studies
- Radiation Detection and Scintillator Technologies
- Photonic Crystal and Fiber Optics
- Integrated Circuits and Semiconductor Failure Analysis
- Particle Detector Development and Performance
- Advanced Optical Imaging Technologies
Active Fiber Systems (Germany)
2024
Friedrich Schiller University Jena
2011-2021
Helmholtz Institute Jena
2019-2020
Fraunhofer Institute for Applied Optics and Precision Engineering
2019
GSI Helmholtz Centre for Heavy Ion Research
2019
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.
Abstract Applications in life sciences and information technology require all‐optical solutions. In the inevitable race towards miniaturized optical circuits, all‐integrated solutions will prevail against bulk setups. Because of its outstanding nonlinear properties, lithium niobate (LiNbO 3 ) emerged as key platform for integrated optics. this paper, we discuss direct femtosecond (fs) laser inscription technique whose flexibility enables realization two‐ three‐dimensional embedded waveguides...
Abstract All optical inscription of quasi phase matching structures in an x‐cut LiNbO 3 crystal is demonstrated. Quasi obtained by periodically lowering the nonlinear refractive index using focussed ultrashort pulses. The were used to frequency double 1.55 µm light. converted signal could be enhanced a factor 70 with respect unmodified material. From these measurement it deduced that nonlinearity has been damped up 20%.
Abstract Optical coherence tomography (OCT) is a non-invasive technique for cross-sectional imaging. It particularly advantageous applications where conventional microscopy not able to image deeper layers of samples in reasonable time, e.g. fast moving, lying structures. However, at infrared and optical wavelengths, which are commonly used, the axial resolution OCT limited about 1 μm, even if bandwidth light covers wide spectral range. Here, we present extreme ultraviolet (XCT) thus...
We present a novel approach to extend optical coherence tomography (OCT) the extreme ultraviolet (XUV) and soft X-ray (SXR) spectral range. With simple setup based on Fourier-domain OCT adapted for application of XUV SXR broadband radiation, cross-sectional images semiconductors organic samples becomes feasible with current synchrotron or laser-plasma sources. For this purpose, radiation is focused onto sample surface, reflected spectrum recorded by an spectrometer. The proposed method has...
We investigate subpicosecond dynamics of warm dense hydrogen at the XUV free-electron laser facility (FLASH) DESY (Hamburg). Ultrafast impulsive electron heating is initiated by a ≤300-fs short x-ray burst 92-eV photon energy. A second pulse probes sample via scattering jitter-free variable time delay. show that initial molecular structure dissociates within (0.9±0.2) ps, allowing us to infer energy transfer rate between electrons and ions. evaluate Saha Thomas-Fermi ionization models in...
Today, coherent imaging techniques provide the highest resolution in extreme ultraviolet (XUV) and X-ray regions. Fourier transform holography (FTH) is particularly unique, providing robust straightforward image reconstruction at same time. Here, we combine two important advances: First, our experiment based on a table-top light source which compact, scalable highly accessible. Second, demonstrate ever achieved with FTH any (34 nm) by utilizing high photon flux cutting-edge nanofabrication...
We report on the absolute sensitivity calibration of an extreme ultraviolet (XUV) spectrometer system that is frequently employed to study emission from short-pulse laser experiments. The XUV spectrometer, consisting a toroidal mirror and transmission grating, was characterized at synchrotron source in respect ratio detected incident photon flux energies ranging 15.5 eV 99 eV. allows determination number emitted by laser-based sources, e.g., high-harmonic generation plasma surfaces or...
We present measurements of photon absorption by free electrons as a solid is transformed to plasma. A femtosecond x-ray free-electron laser used heat solid, which separates the electron and ion heating time scales. The changes in are measured with an independent probe pulse created through high-order-harmonic generation. find increase temperature have relatively small impact on absorption, contrary several predictions, whereas increases absorption. compare data current theoretical numerical...
A key feature of extreme ultraviolet (XUV) radiation from free-electron lasers (FELs) is its spatial and temporal coherence. We measured the spatio-temporal coherence properties monochromatized FEL pulses at 13.5 nm using a Michelson interferometer. time (59±8) fs has been determined, which in good agreement with spectral bandwidth given by monochromator. Moreover, vertical direction amounts to about 15% beam diameter 12% horizontal direction. The feasibility measuring XUV interferometric...
We present a Michelson interferometer for 13.5 nm soft x-ray radiation. It is characterized in proof-of-principle experiment using synchrotron radiation, where the temporal coherence measured to be 13 fs. The curvature of thin-film beam splitter membrane derived from observed fringe pattern. applicability this at intense free-electron lasers investigated, particularly with respect radiation damage. This study highlights potential role such interferometers solid density plasma investigations...
We present an extreme ultraviolet (EUV) microscope using a Schwarzschild objective which is optimized for single-shot sub-micrometer imaging of laser-plasma targets. The has been designed and constructed the scattering from EUV-heated solid-density hydrogen jet. Imaging cryogenic target was demonstrated single pulses free-electron laser in Hamburg (FLASH) at wavelength 13.5 nm. In exposure, we observe jet with ice fragments spatial resolution range. situ EUV expected to enable novel...
We propose to measure the lifetime of short‐lived excited states in highly charged ions by pump‐probe experiments. Utilizing two synchronized and delayed Femtosecond pulses allows accessing these lifetimes with precision. Such measurements could provide sensitive tests state‐of‐the art atomic structure calculations beyond capabilities established methods.
We report on a compact high-photon-flux extreme ultraviolet (XUV) source based high harmonic generation. A XUV-photon flux (>1013 photons/s) is achieved at 21.8 eV and 26.6 eV. The narrow spectral bandwidth (ΔE/E < 10−3) of the generated harmonics in range state-of-the-art synchrotron beamlines enables resolution spectroscopy experiments. robust design fiber–laser system turnkey-controlled even remotely controlled operation outside specialized laser laboratories, which opens...
Dense cryogenic hydrogen is heated by intense femtosecond infrared laser pulses at intensities of 1015-1016 Wcm-2. Three-dimensional particle-in-cell (PIC) simulations predict that this heating limited to the skin depth, causing an inhomogeneously outer shell with a cold core and two prominent temperatures about 25 40 eV for simulated delay times up +70 fs after pulse maximum. Experimentally, time-integrated emitted bremsstrahlung in spectral range 8-18 nm was corrected wavelength-dependent...
We report on the simultaneous determination of non-linear dispersion functions and resolving power three flat-field XUV grating spectrometers. A moderate-intense short-pulse infrared laser is focused onto technical aluminum which commonly present as part experimental setup. In wavelength range 10–19 nm, spectrometers are calibrated using Al-Mg plasma emission lines. This cross-calibration performed in-situ in very same setup actual main experiment. The results excellent agreement with...
We have developed an easy-to-use and reliable timing tool to determine the arrival time of optical laser a free electron (FEL) pulses within jitter limitation. This can be used from XUV X-rays exploits high FELs intensities. It uses shadowgraph technique where we optically (at 800 nm) image plasma created by intense or X-ray FEL pulse on transparent sample (glass slide) directly placed at pump - probe position. is based physical principle that properties material are drastically changed when...
Degenerate plasmas, in which quantum effects dictate the behavior of free electrons, are ubiquitous on earth and throughout space. Transitions between bound electron states determine basic plasma properties, yet degeneracy these transitions have only been theorized. Here, we use an x-ray laser to create characterize a degenerate plasma. We observe core fluorescence spectrum that cannot be reproduced by models ignore degeneracy.We show acts restrict available energy states, thereby slowing...
Short-pulse metrology and dynamic studies in the extreme ultraviolet (XUV) spectral range greatly benefit from interferometric measurements. In this contribution a Michelson-type all-reflective split-and-delay autocorrelator operating quasi amplitude splitting mode is presented. The works under grazing incidence angle broad (10 nm - 1 μm) providing collinear propagation of both pulse replicas thus constant phase difference across beam profile. compact instrument allows for XUV...
Large-scale relativistic calculations are performed for the transition energy and line strength of $ 1s^{2} 2s 2p$ $^1P_{1} \,-\ 2s^{2}$ $^1S_{0} in Be-like carbon. Based on multiconfiguration Dirac-Hartree-Fock~(MCDHF) approach, different correlation models developed to account all major electron-electron contributions. These tested with various sets initial final state wave functions. The uncertainty predicted due missing effects is estimated from differences between results obtained those...
We introduce a high-harmonic generation (HHG)-based XUV source that offers broad photon flux range from 40 eV to 150 eV. This utilizes an industrial-grade TruMicro 2030 laser system with 20-W average power, delivering up 100 µJ pulse durations under 400 fs. A post-compression unit is incorporated reduce the pulses approximately fs just 10% power loss. The turnkey achieves exceeding 10^10 photons/s around 70
We present a highly stable, easy-to-use, table-top coherent XUV source delivering brightness of >1kW/(mm 2 sr)/1%BW at 130eV (9.5nm). IT is based on high-harmonic generation driven by an ultrastable Ytterbium-dope fiber laser and multi-pass-cell post-compression to 35fs.
We present a highly stable, easy-to-use, table-top coherent XUV source delivering brightness of >1kW/(mm²sr)/1%BW at 130eV (9.5nm). It is based on high-harmonic generation driven by an ultrastable ytterbium-based fiber laser and multipass-cell-based post- compression to 35fs.