A5085288290- Laser-Matter Interactions and Applications
- Laser-Plasma Interactions and Diagnostics
- Atomic and Molecular Physics
- Mass Spectrometry Techniques and Applications
- Advanced Chemical Physics Studies
- Advanced Fiber Laser Technologies
- Laser-induced spectroscopy and plasma
- Spectroscopy and Quantum Chemical Studies
- Ion-surface interactions and analysis
- Advanced X-ray Imaging Techniques
- Terahertz technology and applications
- Historical, Literary, and Cultural Studies
- Advanced Electron Microscopy Techniques and Applications
- Particle Accelerators and Free-Electron Lasers
- Medieval European History and Architecture
- Strong Light-Matter Interactions
- Organic Light-Emitting Diodes Research
- Spectroscopy Techniques in Biomedical and Chemical Research
- Botulinum Toxin and Related Neurological Disorders
- Pulsed Power Technology Applications
- Particle accelerators and beam dynamics
- Gold and Silver Nanoparticles Synthesis and Applications
- Laser Design and Applications
- nanoparticles nucleation surface interactions
- Hereditary Neurological Disorders
Max-Born-Institute for Nonlinear Optics and Short Pulse Spectroscopy
2015-2024
Imperial College London
2015-2018
Universität Hamburg
2009-2013
Technische Universität Dresden
2008-2010
The ability to perform attosecond-pump attosecond-probe spectroscopy (APAPS) is a longstanding goal in ultrafast science. While first pioneering experiments demonstrated the feasibility of APAPS, low repetition rates (10 120 Hz) and large footprints existing setups have so far hindered widespread exploitation APAPS. Here, we demonstrate two-color APAPS using commercial laser system at 1 kHz, straightforward post-compression hollow-core fiber, compact high-harmonic generation (HHG) setup....
We report evidence for two previously unidentified effects in the ionization of rare-gas clusters by intense extreme-ultraviolet pulses. First, electron spectra indicate multistep photoemission with increasing isotropy larger due to electron-atom collisions. Second, very slow (meV) electrons are interpreted as first experimental Rydberg-like atomic state formation nanoplasma expansion. Only small fractions Xe2+ ions were found, sharp contrast previous results recorded under comparable...
Multi-electron dynamics in atoms and molecules very often occur on sub- to few-femtosecond timescales. The available intensities of extreme-ultraviolet (XUV) attosecond pulses have previously only allowed the time-resolved investigation two-photon, two-electron interactions. Here we demonstrate control over double triple ionization argon involving absorption up five XUV photons. In an XUV-pump XUV-probe measurement using a pair pulse trains (APTs), Ar$^{2+}$ ion yield exhibits weak delay...
We investigate electron-ion recombination in nanoplasmas produced by the ionization of rare-gas clusters with intense femtosecond extreme-ultraviolet (XUV) pulses. The relaxation dynamics following XUV irradiation is studied using time-delayed 790-nm pulses, revealing generation a large number excited atoms resulting from recombination. In medium-sized Ar-Xe clusters, these are preferentially created Xe core within 10 ps after cluster ionization. serves as sensitive probe for monitoring...
Abstract Intense extreme-ultraviolet (XUV) pulses enable the investigation of XUV-induced non-linear processes and are a prerequisite for development attosecond pump - probe experiments. While highly in XUV range have been studied at free-electron lasers (FELs), high-harmonic generation (HHG) has allowed low-order processes. Here we suggest concept to optimize HHG intensity, which surprisingly requires scaling experimental parameters that differs substantially from optimizing pulse energy....
High-intensity laser pulses covering the ultraviolet to terahertz spectral regions are nowadays routinely generated in a large number of laboratories. In contrast, intense extreme-ultraviolet (XUV) have only been demonstrated using small sources including free-electron facilities [1-3] and long high-harmonic generation (HHG) beamlines [4-9]. Here we demonstrate concept for compact XUV source based on HHG that is focused an intensity $2 \times 10^{14}$ W/cm$^2$, with potential increase up...
We present an organic microcavity laser with wide tunability in the range of 595–650nm, having a threshold as low 2nJ/pulse. The active medium consists composite tris(8-hydroxy quinoline) aluminum (Alq3) and 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) embedded between two distributed Bragg reflectors. inhomogeneously broadened emission from DCM is exploited for lasing by means tunable Fabry–Perot-type interferometer. Continuous tuning achieved varying thickness...
Abstract When an excited atom is embedded into environment, novel relaxation pathways can emerge that are absent for isolated atoms. A well-known example interatomic Coulombic decay, where relaxes by transferring its excess energy to another in the leading ionization. Such processes have been observed clusters ionized extreme-ultraviolet and X-ray lasers. Here, we report on a correlated electronic decay process occurs following nanoplasma formation Rydberg generation ionization of intense,...
The hitherto unexplored two-photon doubly excited states [Ne^{*}(2p^{-1}3s)]_{2} were experimentally identified using the seeded, fully coherent, intense extreme ultraviolet free-electron laser FERMI. These undergo ultrafast interatomic Coulombic decay (ICD), which predominantly produces singly ionized dimers. In order to obtain rate of ICD, resulting yield Ne_{2}^{+} ions was recorded as a function delay between pump and UV probe pulses. extracted lifetimes long-lived states, 390(-130/+450)...
We study two-color high-order harmonic generation in Neon with 790 nm and 1300 driving laser fields observe an extremeultraviolet continuum that extends to photon energies of 160 eV.Using a 6-mm-long, high pressure gas cell, we optimize the HHG yield at investigate effect ionization propagation under phase-matching conditions allow us control temporal structure XUV emission.Numerical simulations include 3D pulse show bright isolated attosecond exceptionally can be generated our experimental...
We study the ionization dynamics of Ar clusters exposed to ultrashort near-infrared (NIR) laser pulses for intensities well below threshold at which tunnel ignites nanoplasma formation. find that emission highly charged ions up Ar^{8+} can be switched on with unit contrast by generating only a few seed electrons an extreme-ultraviolet (XUV) pulse prior NIR field. Molecular simulations explain experimental observations and predict generic scenario where efficient heating via inverse...
We present an optical parametric chirped pulse amplification (OPCPA) system delivering 4.4 TW pulses centered at 810 nm with a sub-9 fs duration and carrier-envelope phase stability of 350 mrad. The OPCPA setup pumped by sub-10 ps from two Yb:YAG thin-disk lasers 100 Hz repetition rate is optimized for high conversion-efficiency. terawatt the are utilized generating intense extreme ultraviolet (XUV) high-order harmonic generation, achieving XUV energies approaching microjoule level.
High-order harmonic generation (HHG) normally requires a careful adjustment of the driving laser intensity (typically ${10}^{14}--{10}^{15}$ W/${\mathrm{cm}}^{2}$) and gas medium parameters to obtain microscopically macroscopically optimized output. In contrast conventional wisdom, we present experimental results indicating efficient HHG in all rare gases, using high-density around ${10}^{16}$ W/${\mathrm{cm}}^{2}$. The are corroborated by theoretical simulations, which indicate that...
Auger decay carries valuable information about the electronic structure and dynamics of atoms, molecules, solids. Here we furnish evidence that under certain conditions electrons are subject to an energetic chirp. The effect is disclosed in time-resolved streaking experiments on Xe NOO Kr MNN using extreme-ultraviolet pulses from free-electron laser Hamburg as well a high-order harmonic source. origin this found be exchange energy between electron earlier emitted correlated photoelectron....
We report on transferring the concept of light-field streaking with intense terahertz fields from free-electron lasers to laboratory scale. Utilizing a commercial laser system, synchronized 300 μm and 13 nm extreme ultraviolet pulses are generated by optical rectification high harmonic generation, respectively. The sufficiently strong support electron wave packet sampling few fs resolution. capability this approach is demonstrated measuring duration formed direct photoemission neon gas target.
We investigate electron-ion recombination processes in clusters exposed to intense extreme-ultraviolet (XUV) or near-infrared (NIR) pulses. Using the technique of reionization excited atoms from (REAR), recently introduced Schütte et al (2014 Phys. Rev. Lett. 112 253401), a large population atoms, which are formed nanoplasma during cluster expansion, is identified under both ionization conditions. For XUV clusters, we find that significance increases for increasing sizes. In addition, larger...
Irradiation of nanoscale clusters and large molecules with intense laser pulses transforms them into highly-excited non- equilibrium states. The dynamics laser-cluster interaction is encoded in electron kinetic energy spectra, which contain signatures direct photoelectron emission as well thermalized nanoplasma electrons. In this work we report on a so far not observed spectrally narrow bound state signature the spectra from mixed Xe core - Ar shell ionized by extreme-ultraviolet (XUV)...
Ne clusters (∼5000 atoms) were resonantly excited (2p→3s) by intense free electron laser (FEL) radiation at FERMI. Such multiply can decay nonradiatively via energy exchange between least two neighboring atoms. Benefiting from the precise tunability and narrow bandwidth of seeded FEL radiation, specific sites probed. We found that relaxation cluster surface atoms proceeds a sequence interatomic or intermolecular Coulombic (ICD) processes while ICD bulk is additionally affected surrounding...
Liquid water at ambient temperature displays ultrafast molecular motions and concomitant fluctuations of very strong electric fields originating from the dipolar H2O molecules. We show that such random intermolecular induce tunnel ionization molecules, which becomes irreversible if an external terahertz (THz) pulse imposes additional directed field on liquid. Time-resolved nonlinear THz spectroscopy maps charge separation, transport, localization released electrons a few-picosecond time...
The ongoing development of intense high-harmonic generation (HHG) sources has recently enabled highly nonlinear ionization atoms by the absorption at least 10 extreme-ultraviolet (XUV) photons within a single atom [Senfftleben \textit{et al.}, arXiv1911.01375]. Here we investigate role that reshaping fundamental, few-cycle, near-infrared (NIR) driving laser 30-cm-long HHG Xe medium plays in pulses. Using an incident NIR intensity is higher than what required for phase-matched HHG, signatures...
We demonstrate Rabi oscillations in nonlinear ionization of argon by an intense femtosecond extreme ultraviolet (XUV) laser field produced high-harmonic generation. monitor the formation $\mathrm{A}{\mathrm{r}}^{2+}$ as a function time delay between XUV pulse and additional near-infrared (NIR) pulse, show that population $\mathrm{A}{\mathrm{r}}^{+*}$ intermediate resonance exhibits strong modulations both due to NIR laser-induced Stark shift XUV-induced cycling ground state...