SKM 2023 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 43: Poster: Plasmonics and Nanooptics I

O 43.1: Poster

Dienstag, 28. März 2023, 18:00–20:00, P2/EG

Quantitative Modeling of Scattering-type Scanning Near-field Optical Microscope (s-SNOM) with the Finite Element Method Utilizing the Software JCMSuite — •Dinghe Dai, Dario Siebenkotten, Richard Ciesielski, and Bernd Kästner — Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin

Scattering-type scanning near-field optical microscopy (s-SNOM), where local field enhancement is created with an oscillating nanotip, is widely applied in the nanoscale characterization of nanostructures, surface polaritons, and biomolecular systems. s-SNOM requires quantitative evaluation schemes with analytical models or simulation methods, among which the Finite Dipole Model [1] is a sophisticated model to calculate the near-field scattering for bulk materials. Nevertheless, it cannot model the full tip size or surface nanostructures. To solve this, a numerical model, based on the finite element method (FEM) software JCMSuite, is developed. The model describes the electromagnetic field over several orders of magnitude in physical size. At various infrared incident wavelengths (µm), the electromagnetic fields are simulated for different tip-sample gaps (nm) and demodulated at harmonics of the tapping frequency to eliminate background field effects. The agreement and deviation of amplitude and phase spectra between both models across multiple demodulation orders are discussed. The FEM by JCMSuite combined with field demodulation is a credible quantitative s-SNOM simulation method especially interesting for complex multilayer and nanooptical structures.

[1] Cvitkovic et al. Optics express 15(14) (2007): 8550-8565.