Humboldt-Universität zu Berlin - Mathematisch-Naturwissen­schaft­liche Fakultät - Institut für Physik

Dr. Franz-Philipp Schmidt (Fritz-Haber-Institut, Department of Inorganic Chemistry, Berlin, Habilitandenkolloquium),
"Spatially resolved plasmon mapping & coupling in an electron microscope"

Abstract:
Nanoscale light management and manipulation is of increasing interest to meet the needs for novel photonic devices, such as miniaturized photonic circuits, novel light sources and ultrasensitive biosensors. Surface plasmons play an important role in this quest, as they confine light close to a metallic surface, on a scale smaller than the light wavelength. This opens new possibilities to use and control light below the diffraction limit for further miniaturization.
In this talk, I will give an overview of electron beam based plasmonics, starting with nanoscale plasmon mapping of individual nanoparticles, plasmon-plasmon coupling within and between defined nanostructures, plasmon-exciton coupling and plasmon-phonon coupling. The experimental results – gained by electron energy loss spectroscopy (EELS) and cathodoluminescence (CL) within a transmission electron microscope (TEM)– are supported by theory (boundary element method (BEM)). From these findings, fundamental aspects of localized plasmonic eigenmodes, such as the energy-momentum relation, are derived and linked to propagating plasmons in 1D (edge plasmons) and 2D (film plasmons). Furthermore, the role of transmitters to couple light in and out of metallic nanostructures will be discussed. Therefore, multi-step electron beam lithography (EBL) is applied to allow precise positioning of coupling partners (metallic nanostructures (plasmons), quantum dots/dye molecules (excitons), substrate (phonons)).
I will finish this talk with an outlook on how localized light fields might be used to enable the visualization of a single active center, a long-awaited goal in catalysis research.

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