429 citations · 1.1k across the 16 of their papers we have counts for
16 papers
Revealing domain wall stability during ultrafast demagnetization
Hung-Tzu Chang, Sergey Zayko, Timo Schmidt +5
The ultrafast control of nanoscale spin textures such as magnetic domain walls or skyrmions is essential for advancing high-speed, high-density spintronics. However, imaging their…
Observation of quantum entanglement between free electrons and photons
Jan-Wilke Henke, Hao Jeng, Murat Sivis +1
Quantum entanglement is central to both the foundations of quantum mechanics and the development of new technologies in information processing, communication, and sensing. Entangle…
Roadmap for Quantum Nanophotonics with Free Electrons
F. Javier García de Abajo, Albert Polman, Cruz I. Velasco +44
Over the past century, continuous advancements in electron microscopy have enabled the synthesis, control, and characterization of high-quality free-electron beams. These probes ca…
Attosecond electron microscopy by free-electron homodyne detection
John H. Gaida, Hugo Lourenço-Martins, Murat Sivis +4
Time-resolved electron microscopy aims at tracking nanoscale excitations and dynamic states of matter with a temporal resolution ultimately reaching the attosecond regime. Periodic…
High-sensitivity extreme-ultraviolet transient absorption spectroscopy enabled by machine learning
Tobias Heinrich, Hung-Tzu Chang, Sergey Zayko +2
We introduce a machine-learning-based approach to enhance the sensitivity of optical-extreme ultraviolet (XUV) transient absorption spectroscopy. A reference spectrum is used as in…
Electronic and structural fingerprints of charge density wave excitations in extreme ultraviolet transient absorption spectroscopy
Tobias Heinrich, Hung-Tzu Chang, Sergey Zayko +3
Femtosecond core-level transient absorption spectroscopy is utilized to investigate photoinduced dynamics of the charge density wave in 1T-TiSe2 at the Ti M2,3 edge (30-50 eV). Pho…
Ultrafast high-harmonic nanoscopy of magnetization dynamics
Sergey Zayko, Ofer Kfir, Michael Heigl +4
Light-induced magnetization changes, such as all-optical switching, skyrmion nucleation, and intersite spin transfer, unfold on temporal and spatial scales down to femtoseconds and…
Chiral high-harmonic generation and spectroscopy on solid surfaces using polarization-tailored strong fields
Tobias Heinrich, Marco Taucer, Ofer Kfir +4
Strong-field methods in solids enable new strategies for ultrafast nonlinear spectroscopy and provide all-optical insights into the electronic properties of condensed matter in rec…
Clocking plasmon nanofocusing by THz near-field streaking
Lara Wimmer, Benjamin Schröder, Murat Sivis +2
We apply terahertz (THz) near-field streaking in a nanofocusing geometry to investigate plasmon polariton propagation on the shaft of a conical nanotip. By evaluating the delay bet…
Spontaneous and Stimulated Electron-Photon Interactions in Nanoscale Plasmonic Near Fields
Matthias Liebtrau, Murat Sivis, Armin Feist +6
We demonstrate spatially-resolved measurements of spontaneous and stimulated electron-photon interactions in nanoscale optical near fields using electron energy-loss spectroscopy (…
Controlling free electrons with optical whispering-gallery modes
Ofer Kfir, Hugo Lourenço-Martins, Gero Storeck +5
Free-electron beams serve as uniquely versatile probes of microscopic structure and composition, and have repeatedly revolutionized atomic-scale imaging, from solid-state physics t…
Continuous-Wave Multiphoton Photoemission from Plasmonic Nanostars
Murat Sivis, Nicolas Pazos-Perez, Renwen Yu +3
Highly nonlinear optical processes, such as multiphoton photoemission, require high intensities, typically achieved with ultrashort laser pulses and, hence, were first observed wit…
Nanoscale Magnetic Imaging using Circularly Polarized High-Harmonic Radiation
Ofer Kfir, Sergey Zayko, Christina Nolte +10
This work demonstrates nanoscale magnetic imaging using bright circularly polarized high-harmonic radiation. We utilize the magneto-optical contrast of worm-like magnetic domains i…
Phase-ordering of charge density waves traced by ultrafast low-energy electron diffraction
S. Vogelgesang, G. Storeck, S. Schramm +3
We introduce ultrafast low-energy electron diffraction (ULEED) in backscattering for the study of structural dynamics at surfaces. Using a tip-based source of ultrashort electron p…
Ultrafast transmission electron microscopy using a laser-driven field emitter: femtosecond resolution with a high coherence electron beam
Armin Feist, Nora Bach, Nara Rubiano da Silva +12
We present the development of the first ultrafast transmission electron microscope (UTEM) driven by localized photoemission from a field emitter cathode. We describe the implementa…
Generation and Bistability of a Waveguide Nanoplasma Observed by Enhanced Extreme-Ultraviolet Fluorescence
Murat Sivis, Claus Ropers
We present a study of the highly nonlinear optical excitation of noble gases in tapered hollow waveguides using few-femtosecond laser pulses. The local plasmonic field enhancement…