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O: Fachverband Oberflächenphysik

O 96: Plasmonics and Nanooptics: Light-Matter Interaction, Spectroscopy II

O 96.3: Vortrag

Freitag, 21. März 2025, 11:00–11:15, H4

Full-wave simulations of core-shell nanoparticle investigation by tapping mode near-field optical microscopy — •Dario Siebenkotten, Dinghe Dai, Richard Ciesielski, Arne Hoehl, and Bernd Kästner — Physikalisch-Technische Bundesanstalt, Abbestr. 2-12 10587 Berlin

Core-shell nanoparticles are important in applications such as optoelectronics, biosensing, and medicine, where their unique optical and geometric properties play a critical role in functionality. Quantifying the properties of both, the core and the shell, is crucial to understand the nanoparticle’s ultimate functionality. However, optical investigation of their properties, while widely employed, is generally diffraction-limited and thus unsuitable for the investigation of individual nanoparticles, as they only provide averaged ensemble information. Scattering-type scanning near-field optical microscopy (s-SNOM) promises access to a single nanoparticle’s size and optical properties through the use of an atomic force microscopy tip as an optical antenna, which confines the sampling fields to nanoscale dimensions. To explore the single nanoparticle s-SNOM response, we model different core-shell nanoparticles using Finite Element Modelling, revealing complex resonance-antiresonance behaviour in dependence of their geometrical and optical properties. We further explore the origin of the emergent antiresonance through the use of Fourier-demodulation of the probe tapping [1], closely mimicking the experiment.
[1] Mooshammer et al., ACS Photonics 7, 344-351 (2020)

Keywords: s-SNOM; near-field microscopy; Core-Shell nanoparticles; Finite Element Method