Dresden 2026 – scientific programme
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O: Fachverband Oberflächenphysik
O 26: Plasmonics and nanooptics: Fabrication, characterization and applications – Poster
O 26.4: Poster
Monday, March 9, 2026, 18:00–20:00, P2
Is the linkng number a topological invariant? — •Maja Manten1, Alexander Neuhaus1, Pascal Dreher1, Phillip Gessler1, Bettina Frank2, Tim Davis1,2,3, Harald Giessen2, Michael Horn-von Hoegen1, Karin Everschor-Sitte1, and Frank Meyer zu Heringdorf1 — 1Faculty of Physics and Center for Nanointegration, Duisburg-Essen (CENIDE), University of Duisburg-Essen, 47048 Duisburg, Germany. — 24th Physics Institute, Research Center SCoPE, and Integrated Quantum Science and Technology Center, University of Stuttgart, Germany. — 3School of Physics, University of Melbourne, Parkville, Victoria 3010 Australia
Optical near fields, like they occur in surface plasmon polaritons, exhibit a wide range of topological textures, including skyrmions, merons, and optical vortices carrying orbital angular momentum. Near fields that carry a fractional orbital angular momentum rather than integer orbital angular momentum, however, pose a challenge: they form a complex phase-vortex landscape and break the simple picture of a single vortex carrying the topological charge. When the fields become distorted, the situation becomes more complicated as more and more vortices appear. The sequence of vortices and antivortices can extend to infinity and evade global topological classification in real space. Here we show that a global topological invariant, the linking number, can be found in Fourier space. We show how the linking number of a plasmonic field can be determined from a time resolved polarimetric photoemission microscopy experiment and demonstrate the robustness of the linking number against deformation of the excitation structure.
Keywords: Plasmonics; Topology; OAM; PEEM