1,720,970 research outputs found
Structural dynamics probed by high-coherence electron pulses
No full textUltrafast measurement technology provides essential contributions to our understanding of the properties and functions of solids and nanostructures. Atomic-scale vistas with ever-growing spatial and temporal resolution are offered by methods based on short pulses of x-rays and electrons. Time-resolved electron diffraction and microscopy are among the most powerful approaches to investigate nonequilibrium structural dynamics. In this article, we discuss recent advances in ultrafast electron imaging enabled by significant improvements in the coherence of pulsed electron beams. Specifically, we review the development and first application of ultrafast low-energy electron diffraction for the study of structural dynamics at surfaces, and discuss novel opportunities for ultrafast transmission electron microscopy facilitated by laser-triggered field-emission sources. These and further developments will render coherent electron beams an essential component in future ultrafast nanoscale imaging. Introduction
Structural dynamics in atomic indium wires on silicon: From ultrafast probing to coherent vibrational control
No full texthttp://dx.doi.org/10.13039/501100003006 ETH Zürichhttp://dx.doi.org/10.13039/100010663 ERChttp://dx.doi.org/10.13039/501100000781 European Research Councilhttp://dx.doi.org/10.13039/501100001659 DF
Nanotip-based photoelectron microgun for ultrafast LEED
Full text linkWe present the design and fabrication of a micrometer-scale electron gun for the
implementation of ultrafast low-energy electron diffraction from surfaces. A multi-step
process involving photolithography and focused-ion-beam nanostructuring is used to assemble and
electrically contact the photoelectron gun, which consists of a nanotip photocathode in a
Schottky geometry and an einzel lens for beam collimation. We characterize the low-energy
electron pulses by a transient electric field effect and achieve pulse durations of 1.3 ps
at an electron energy of 80 eV. First diffraction images in a backscattering geometry (at 50
eV electron energy) are shown
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