A5042132769- Laser-Matter Interactions and Applications
- Laser-induced spectroscopy and plasma
- Laser-Plasma Interactions and Diagnostics
- Advanced X-ray Imaging Techniques
- Quantum, superfluid, helium dynamics
- Advanced Electron Microscopy Techniques and Applications
- Spectroscopy and Quantum Chemical Studies
- Mass Spectrometry Techniques and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- High-pressure geophysics and materials
- X-ray Spectroscopy and Fluorescence Analysis
- Atomic and Subatomic Physics Research
- Digital Holography and Microscopy
- Laser Material Processing Techniques
- Advanced Fiber Laser Technologies
- Crystallography and Radiation Phenomena
- Ion-surface interactions and analysis
- Spectroscopy and Laser Applications
- Electron and X-Ray Spectroscopy Techniques
- Advanced Optical Sensing Technologies
- nanoparticles nucleation surface interactions
- Microfluidic and Bio-sensing Technologies
- Micro and Nano Robotics
- Advanced Chemical Physics Studies
- Advanced Fluorescence Microscopy Techniques
University of Rostock
2014-2025
Mater Dei Hospital
2018
University Hospitals Sussex NHS Foundation Trust
2018
Abstract The diversity of nanoparticle shapes generated by condensation from gaseous matter reflects the fundamental competition between thermodynamic equilibration and persistence metastable configurations during growth. In kinetically limited regime, intermediate geometries that are favoured only in early formation stages can be imprinted finally observed ensemble differently structured specimens. Here we demonstrate single-shot wide-angle scattering femtosecond soft X-ray free-electron...
Abstract Near-fields of non-resonantly laser-excited nanostructures enable strong localization ultrashort light fields and have opened novel routes to fundamentally modify control electronic strong-field processes. Harnessing spatiotemporally tunable near-fields for the steering sub-cycle electron dynamics may ultrafast optoelectronic devices unprecedented in generation attosecond photon pulses. Here we utilize unsupported sub-wavelength dielectric nanospheres generate with adjustable...
Abstract Coherent diffractive imaging of individual free nanoparticles has opened routes for the in situ analysis their transient structural, optical, and electronic properties. So far, single-shot single-particle diffraction was assumed to be feasible only at extreme ultraviolet X-ray free-electron lasers, restricting this research field large-scale facilities. Here we demonstrate isolated helium nanodroplets using pulses from a femtosecond-laser-driven high harmonic source. We obtain...
A significant fraction of superfluid helium nanodroplets produced in a free-jet expansion has been observed to gain high angular momentum resulting large centrifugal deformation. We measured single-shot diffraction patterns individual rotating up scattering angles using intense extreme ultraviolet light pulses from the FERMI free-electron laser. Distinct asymmetric features wide-angle enable unique and systematic identification three-dimensional droplet shapes. The analysis data set allows...
We introduce a microscopic particle-in-cell approach that allows bridging the and macroscopic realms of laser-driven plasma physics. As first application, resonantly driven cluster nanoplasmas are investigated. Our analysis reveals an attosecond plasma-wave dynamics in clusters with radii R is approximately equal to 30 nm. The waves excited by electrons recolliding surface travel toward center, where they collide break. In this process, energetic electron hot spots generated along highly...
We report on time-resolved coherent diffraction imaging of gas-phase silver nanoparticles, strongly heated via their plasmon resonance. The x-ray images reveal a broad range phenomena for different excitation strengths, from simple melting over strong cavitation to explosive disintegration. Molecular dynamics simulations fully reproduce this behavior and show that the heating induces rather similar trajectories through phase diagram in all cases, with very outcomes resulting solely whether...
Waveform-controlled light fields offer the possibility of manipulating ultrafast electronic processes on sub-cycle timescales. The optical lightwave control collective electron motion in nanostructured materials is key to design devices operating at up petahertz frequencies. We have studied directional emission from 95 nm diameter SiO2 nanoparticles few-cycle laser with a well-defined waveform. Projections three-dimensional (3D) momentum distributions were obtained via single-shot...
Abstract In the strong-field photoemission from atoms, molecules, and surfaces, fastest electrons emerge tunneling subsequent field-driven recollision, followed by elastic backscattering. This rescattering picture is central to attosecond science enables control of electron’s trajectory via sub-cycle evolution laser electric field. Here we reveal a so far unexplored route for waveform-controlled electron acceleration emerging forward in resonant plasmonic systems. We studied plasmon-enhanced...
A complete time-resolved x-ray imaging experiment of laser heated solid-density hydrogen clusters is modeled by microscopic particle-in-cell simulations that account self-consistently for the cluster dynamics and electromagnetic wave evolution. technique developed to retrieve anisotropic nanoplasma expansion from elastic inelastic scattering data. Our method takes advantage self-similar evolution density enables us make movies ultrafast pump-probe experiments.
Nanostructures exposed to ultrashort waveform-controlled laser pulses enable the generation of enhanced and highly localized near fields with adjustable local electric field evolution. Here, we study dielectric SiO2 nanospheres (d = 100–700 nm) under strong carrier-envelope phase-controlled few-cycle perform a systematic theoretical analysis resulting near-field driven photoemission. In particular, analyze impacts charge interaction ellipticity on electron acceleration. Our semiclassical...
The free expansion of a planar plasma surface is fundamental non-equilibrium process relevant for various fields but as-yet experimentally still difficult to capture. significance the associated spatiotemporal motion ranges from astrophysics and controlled fusion laser machining, high-harmonic generation, mirrors, laser-particle acceleration. Here, we show that x-ray coherent diffractive imaging can surpass existing approaches enables quantitative real-time analysis sudden nanoplasmas. For...
We discuss a microscopic particle-in-cell (MicPIC) approach that allows bridging of the and macroscopic realms laser-driven plasma physics. The simultaneous resolution collisions electromagnetic field propagation in MicPIC enables investigation processes have been inaccessible to rigorous numerical scrutiny so far. This is illustrated by two main findings our analysis pre-ionized, resonantly clusters, which can be realized experimentally pump–probe experiments. In linear response regime,...
Intense and temporally structured x-ray laser fields enable the controlled generation of strongly coupled nonequilibrium cluster nanoplasmas time-resolved investigation their dynamics. Recent femtosecond pump-probe experiments on xenon clusters revealed subpicosecond relaxation dynamics in nanoplasma via delay-dependent charge states emitted atomic ions [M. Krikunova et al., J. Phys. B: At. Mol. Opt. 45, 105101 (2012)]. Here we report a scheme based local electron single-particle energy...
Shortening the laser pulse length opens up new opportunities for desorption (LD) of molecules, with benefits mass spectrometry (MS) sampling and ionization. The capability to ablate any material without need an absorbing matrix decrease thermal damage molecular fragmentation has promoted various applications very different parameters postionization techniques. However, key issues optimum intensity achieve efficient gentle molecules in MS are not resolved, although these determine costs...
Two-component nanoplasmas generated by strong-field ionization of doped helium nanodroplets are studied in a pump–probe experiment using few-cycle laser pulses combination with molecular dynamics simulations. High yields ions and pronounced resonance structure the transients which is droplet size dependent reveal evolution dopant-induced nanoplasma an active role for He shells ensuing dynamics. The interpreted terms strong inner pump pulse resonant heating probe controls final charge states...
The formation of an electron–hole plasma during the interaction intense femtosecond laser pulses with transparent solids lies at heart processing. Advanced micro- and nanomachining applications require improved control over excitation characteristics. Here, we relate emission low-order harmonics to strong laser-field-induced formation. Together a measurement total density, identify contribution two competing ionization mechanisms─strong-field electron-impact ionization.
Abstract We explore the light induced dynamics in superfluid helium nanodroplets with wide-angle scattering a pump–probe measurement scheme. The droplets are doped xenon atoms to facilitate ignition of nanoplasma through irradiation near-infrared laser pulses. After variable time delay up 800 ps, we image subsequent using intense extreme ultraviolet pulses from FERMI free-electron laser. recorded images exhibit complex intensity fluctuations that categorized based on their characteristic...
The structure and dynamics of isolated nanosamples in free flight can be directly visualized via single-shot coherent diffractive imaging using the intense short pulses X-ray free-electron lasers. Wide-angle scattering images even encode three-dimensional morphological information samples, but retrieval this remains a challenge. Up to now, effective morphology reconstructions from single shots were only achieved fitting with highly constrained models, requiring priori knowledge about...
Clusters and nanoparticles have been widely investigated to determine how plasmonic near fields influence the strong-field induced energetic electron emission from finite systems. We focus on contrary, i.e., slow electrons, discuss a hitherto unidentified low-energy structure (LES) in photoemission spectra of rare gas clusters intense near-infrared laser pulses. For Ar Kr we find, besides field-driven fast robust nearly isotropic electrons with $<4\text{ }\text{ }\mathrm{eV}$ kinetic...
The dynamics of solid‐density nanoplasmas driven by intense lasers takes place in the strongly‐coupled plasma regime, where collisions play an important role. microscopic particle‐in‐cell method has enabled complete classical electromagnetic description these processes. theoretical foundation approach and its relation to existing methods are reviewed. Selected applications laser cluster processes presented that have been inaccessible numerical simulation so far.
We introduce a complex scaling discrete dipole approximation (CSDDA) method and study single-shot x-ray diffraction patterns from non-spherical, absorbing nanotargets in the limit of linear response. The convergence employed Born series-based iterative solution problem via optimal mixing turns out to be substantially faster than original approach with real-valued coefficients, without additional numerical effort per iteration. CSDDA is calculate soft large icosahedral silver nanoparticles...