Berlin 2024 – scientific programme

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O: Fachverband Oberflächenphysik

O 24: Plasmonics and Nanooptics III: Light-Matter Interaction and Spectroscopy

O 24.2: Talk

Tuesday, March 19, 2024, 10:45–11:00, MA 042

Near - field optical microscopy of complex plasmonic excitations — •Farid Aghashirinov, Anant Mantha, Florian Mangold, Julian Schwab, Bettina Frank, and Harald Giessen — 4-th Physics Institute, University of Stuttgart, Stuttgart, Germany

We experimentally and theoretically study surface plasmon polaritons (SPPs) on single crystalline gold platelets of both long- and short-range type. Short-range surface plasmon polaritons (SR-SPPs) have received less attention compared to long-range SPPs (LR-SPPs) due to high attenuation losses, which shortens their propagation length. To investigate the complex SPP near - field pattern on single crystalline gold platelet, we utilize a reflection s - SNOM combined with a tunable broadband laser source. We disentangle excitations coming both from the scanning tip and the gold platelet edges by applying a Fourier analysis method. This allows us to determine the SPP wavelength and furthermore identify hidden excitations that are covered by interference of other waves. Fourier filtering makes it possible to identify the propagation direction of short-range surface plasmon polaritons, as well as their propagation length. In addition, we explore the impact of platelet thickness on the short - range SPP wavelength, which in future will give us another tuning parameter for scaling and combining complex near - field optical microscopy with topological plasmonics.

Keywords: Surface plasmon polaritons; Single crystalline gold plateletss; Scattering SNOM; Near - field optics; Tunable broadband laser