Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 78: Plasmonics and Nanooptics 3
O 78.5: Vortrag
Freitag, 9. September 2022, 11:30–11:45, H3
Mode-selective imaging and control of nano-plasmonic near-fields — •Murat Sivis1,2, Hugo Lourenço-Martins1,2, Andre Geese2, Tyler R. Harvey2, Thomas Danz1,2, Radwan M. Sarhan3, Matias Bargheer3, Armin Feist1,2, and Claus Ropers1,2 — 1Max Plank Institute for Multidisciplinary Sciences, Göttingen, Germany — 24th Physical Institute - Solids and Nanostructures, University of Göttingen, Germany — 3Institut für Physik und Astronomie, Universität Potsdam, Potsdam, Germany
Electron energy-loss spectroscopy (EELS) in a transmission electron microscope allows for the study of optical excitations in plasmonic nanostructures with sub-nanometer spatial resolution. While EELS is a powerful tool, it can only provide information about the spontaneous losses in a system with limited spectral resolution (10-100 meV in the most advanced microscopes). Recent developments in ultrafast transmission electron microscopy overcome these limitations and enable the probing of laser-excited modes by using photon-induced near-field electron microscopy (PINEM). Here, we demonstrate how PINEM can be used to measure the modal structure of the optical response of individual plasmonic systems (metal nano-triangle-resonators) at the nanoscale. Using our boundary element method (BEM)-based data analysis, we extract the magnitude and relative phase of each plasmonic mode from optical near-field maps. This approach opens a route to study the influence of the laser polarization, wavelength and incidence angle on the population of each mode, as well as the control of complex mode patterns created by multicolor fields.