A5013633580- Advanced Electron Microscopy Techniques and Applications
- Near-Field Optical Microscopy
- Semiconductor Quantum Structures and Devices
- Nanowire Synthesis and Applications
- Force Microscopy Techniques and Applications
- Electron and X-Ray Spectroscopy Techniques
- Advanced X-ray Imaging Techniques
- Laser-Matter Interactions and Applications
- Orbital Angular Momentum in Optics
- Semiconductor materials and interfaces
- Integrated Circuits and Semiconductor Failure Analysis
- Photonic and Optical Devices
- Ion-surface interactions and analysis
- Advanced Fluorescence Microscopy Techniques
- Plasmonic and Surface Plasmon Research
- Quantum Dots Synthesis And Properties
- Random lasers and scattering media
- Semiconductor materials and devices
- Perovskite Materials and Applications
- Magnetic properties of thin films
- 2D Materials and Applications
- Graphene research and applications
- Chalcogenide Semiconductor Thin Films
- Silicon Nanostructures and Photoluminescence
- Mechanical and Optical Resonators
University of Milano-Bicocca
2020-2024
École Polytechnique Fédérale de Lausanne
2017-2024
California Institute of Technology
2012-2023
Wuhan National Laboratory for Optoelectronics
2017
Huazhong University of Science and Technology
2017
University of Colorado Boulder
2017
Politecnico di Milano
2009-2015
National Interuniversity Consortium for the Physical Sciences of Matter
2010-2015
NOAA Chemical Sciences Laboratory
2011
Universidade Estadual de Campinas (UNICAMP)
2009
Light-electron interaction in empty space is the seminal ingredient for free-electron lasers and also controlling electron beams to dynamically investigate materials molecules. Pushing coherent control of free electrons by light unexplored timescales, below attosecond, would enable unprecedented applications light-assisted quantum circuits diagnostics at extremely small such as those governing intramolecular electronic motion nuclear phenomena. We experimentally demonstrate attosecond...
We demonstrate that light-induced heat pulses of different duration and energy can write skyrmions in a broad range temperatures magnetic field FeGe. Using combination camera-rate pump-probe cryo-Lorentz Transmission Electron Microscopy, we directly resolve the spatio-temporal evolution magnetization ensuing optical excitation. The skyrmion lattice was found to maintain its structural properties during laser-induced demagnetization, recovery initial state happened sub-{\mu}s {\mu}s range,...
The electronic, optical, and magnetic properties of quantum solids are determined by their low-energy (<100 meV) many-body excitations. Dynamical characterization manipulation such excitations rely on tools that combine nm-spatial, fs-temporal, meV-spectral resolution. Currently, phonons collective plasmon resonances can be imaged in nanostructures with atomic (sub-nm) tens meV space/energy resolution using state-of-the-art energy-filtered transmission electron microscopy (TEM), but only...
The quantum interference between ultrafast light and electron pulses enables the holographic reconstruction of nanoscale fields.
Spatiotemporal electron-beam shaping is a bold frontier of electron microscopy. Over the past decade, methods evolved from static phase plates to low-speed electrostatic and magnetostatic displays. Recently, swift change paradigm utilizing light control free electrons has emerged. Here, we experimentally demonstrate arbitrary transverse modulation beams without complicated electron-optics elements or material nanostructures, but rather using shaped beams. On-demand spatial wavepackets...
Understanding and actively controlling the spatiotemporal dynamics of nonequilibrium electron clouds is fundamental for design light sources, high-power electronic devices, plasma-based applications. However, evolve in a complex collective fashion on nanometer femtosecond scales, producing electromagnetic screening that renders them inaccessible to existing optical probes. Here, we solve long-standing challenge characterizing evolution generated upon irradiation metallic structures using an...
Significance The biomechanics of amyloid underlies its function in living organisms. We use four-dimensional electron microscopy to systematically dissect the nanoscale origins elasticity by measuring bond stiffnesses intermolecular forces stabilizing each three characteristic packing interfaces. find have a pronounced mechanical anisotropy with longitudinal, hydrogen bonding 20 times stiffer than transverse, amphiphilic, and electrostatic interactions. Such strongly anisotropic elastic...
Significance Rippling is an intrinsic feature of 2D materials, responsible for their structural stability, transport properties, and electron–hole charge redistribution. Modulating these ripples in a controlled manner not only provides better understanding but also has potential impact applications. Here, we examine graphene monolayer as prototypical material. An ultrafast attenuation the intrinsically present plane followed by significant enhancement rippling effect on longer time scale,...
The most common MXene composition Ti3C2Tx (T = F, O) shows outstanding stability as anode for sodium ion batteries (100% of capacity retention after 530 cycles with charge efficiency >99.7%). However, the reversibility intercalation/deintercalation process is strongly affected by synthesis parameters determining, in turn, significant differences material structure. This study proposes a new approach to identify crystal features influencing performances, using structural model built...
The ultrafast dynamics of charge carriers in solids plays a pivotal role emerging optoelectronics, photonics, energy harvesting, and quantum technology applications. However, the investigation direct visualization such nonequilibrium phenomena remains as long-standing challenge, owing to nanometer-femtosecond spatiotemporal scales at which evolve. Here, we propose demonstrate an interaction mechanism enabling nanoscale imaging femtosecond solids. This modality, name electron microscopy...
Phase-change materials (PCMs) represent the leading candidates for universal data storage devices, which exploit large difference in physical properties of their transitional lattice structures. On a nanoscale, it is fundamental to determine performance, ultimately controlled by speed limit transformation among different structures involved. Here, we report observation with atomic-scale resolution transient nanofilms crystalline germanium telluride, prototypical PCM, using ultrafast electron...
The ability to manipulate particles has always been a fundamental aspect for developing and improving scattering microscopy techniques used material investigations. So far, applications have mostly relied on classical treatment of the electron-matter interaction. However, exploiting particle's quantum nature can reveal novel information not accessible with conventional schemes. Here, after describing recent methods coherent wave function engineering, we discuss how manipulation electrons, He...
Abstract The past decade has witnessed a quantum revolution in the field of computation, communication and materials investigation. A similar is also occurring for free-electron based techniques, where classical treatment free electron as point particle being surpassed toward deeper exploitation its nature. Adopting familiar concepts from optics, several groups have demonstrated temporal spatial shaping wave function, developing theoretical descriptions light-modulated states, well...
Cryo-electron microscopy is a form of transmission electron that has been used to determine the 3D structure biological specimens in hydrated state and with high resolution. We report development 4D cryo-electron by integrating fourth dimension, time, into this powerful technique. From time-resolved diffraction amyloid fibrils thin layer vitrified water at cryogenic temperatures, we were able detect picometer movements protein molecules on nanosecond time scale. Potential future applications...
Abstract Characterizing and controlling the out-of-equilibrium state of nanostructured Mott insulators hold great promises for emerging quantum technologies while providing an exciting playground investigating fundamental physics strongly-correlated systems. Here, we use two-color near-field ultrafast electron microscopy to photo-induce insulator-to-metal transition in a single VO 2 nanowire probe ensuing electronic dynamics with combined nanometer-femtosecond resolution (10 −21 m ∙ s). We...
Single-pixel imaging, originally developed in light optics, facilitates fast three-dimensional sample reconstruction as well probing with wavelengths undetectable by conventional multi-pixel detectors. However, the spatial resolution of optics-based single-pixel microscopy is limited diffraction to hundreds nanometers. Here, we propose an implementation imaging relying on attainable modifications currently available ultrafast electron microscopes which optically modulated electrons are used...
The complex range of interactions between electrons and electromagnetic fields gave rise to countless scientific technological advances. A prime example is photon-induced nearfield electron microscopy (PINEM), enabling the detection confined electric in illuminated nanostructures with unprecedented spatial resolution. However, PINEM limited by its dependence on strong fields, making it unsuitable for sensitive samples, inability resolve phasor information. Here, we leverage nonlinear,...
Unlike in bulk materials, energy transport low-dimensional and nanoscale systems may be governed by a coherent "ballistic" behavior of lattice vibrations, the phonons. If dominant, such would determine mechanism for relaxation various energy-conversion applications. In order to study this limit, both spatial temporal resolutions must sufficient length-time scales involved. Here, we report observation dynamics quantum dots gallium arsenide using ultrafast electron diffraction. By varying dot...
Significance Mechanical, electrical, and thermal properties of materials are governed by the nature constituent atoms their motions. Mapping atomic motions in nonequilibrium regime, thus linear nonlinear responses to stimuli, is nontrivial achieve. Here, we report methodology ultrafast electron diffraction, enabling visualization motion. By using a special variant called Kikuchi map out response lattice nanoscale graphite. Following an impulsive excitation, two types resolved, one involving...
The coupling between electronic and nuclear degrees of freedom in low-dimensional, nanoscale systems plays a fundamental role shaping many their properties. Here, we report the disentanglement axial radial expansions carbon nanotubes, direct vibrational excitations determining such expansions. With subpicosecond subpicometer resolutions, structural dynamics were explored by monitoring changes electron diffraction following an ultrafast optical excitation, whereas transient behavior charge...