Berlin 2024 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 14: Plasmonics and Nanooptics II: Light-Matter Interaction and Spectroscopy

O 14.4: Vortrag

Montag, 18. März 2024, 16:00–16:15, MA 042

Electron driven photon sources for engineered generation of light propagating in Free Space — •Masoud Taleb and Nahid Talebi — Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Germany

Optical beams with angular momentum have been intensively investigated for offering an additional degree of freedom for information transfer or manipulating the chiral degrees of freedom in matter. Such beams are generally realized via metasurfaces, photon sieves, or structured lenses. However, most of them lack key properties in controlling the polarization, directionality and intensity of the light which is generated and directed from a localized radiation sources such as electron beam induced emission. Previously, we have realized electron-driven photon sources which are fabricated by specific orders of nanoholes in a thin layer of gold (Nano Lett. 2020, 20, 8, 5975*5981). Here, we further elucidate on a variety of degrees of freedom in our design principle to both control the polarization and the shape of the generated light. A moving electron at the kinetic energy of 30 kV interacts with the system acting as a broadband source of optical excitation. Coupled plasmon polaritons propagate on the lattice forming a chain plasmon polaritons, that further radiates to the far field and generates a vortex beam. This phenomenon is experimentally studied utilizing cathodoluminescence spectroscopy and angle-resolved mapping.