Regensburg 2019 – wissenschaftliches Programm

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SYSD: Symposium SKM Dissertation-Prize 2019

SYSD 1: SKM Dissertation Prize

SYSD 1.6: Hauptvortrag

Montag, 1. April 2019, 11:10–11:30, H2

Ultrafast plasmon-driven point-projection electron microscopy — •Jan Vogelsang, Germann Hergert, Andreas Wöste, Petra Groß, and Christoph Lienau — Institut für Physik, Carl von Ossietzky Universität, 26129 Oldenburg, Germany

Ultrafast electron microscopy opens a path towards spatially resolving ultrafast processes as they happen on the femtosecond time and nanometer length scale. It demonstrates its strength when ensemble-averaging methods are not sufficient anymore to unravel nanoscale dynamics like the coherent charge transfer in new types of solar cells or nanoplasmonic processes in ultrafast optical devices. Still, a time resolution of less than 100 fs has not been demonstrated in a spatially resolved experiment so far. Electron pulses disperse as they propagate, which limits the temporal resolution. We circumvent this problem by reducing the electron propagation distance to only a few 100 nm.

As a prerequisite, we demonstrate for the first time an ultrafast electron point source driven by adiabatic nanofocusing of surface plasmon polaritons. It permits 50 times more efficient electron emission from the apex of a gold tip without illuminating the apex directly.

The direct consequence is the demonstration of electron microscopy experiments with an unprecedented temporal resolution of less than 25 fs. We watch the charge separation in the gap of a single nanoresonator with this plasmon-driven electron microscope.

In a last step, the microscope is further developed to perform electron holography with sub-10-nm spatial resolution and electron spectroscopy without sacrificing the temporal resolution.