Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 36: Plasmonics and Nanooptics

O 36.17: Poster

Tuesday, March 17, 2015, 18:15–21:00, Poster A

Simulations of s-SNOM Systems — •Lisa Ortmann, A. Hille, S.C. Kehr, and L.M. Eng — Institut für Angewandte Physik, George-Bähr-Straße 1, 01069 Dresden

Scattering scanning near-field optical microscopy (s-SNOM) utilizes scattering of electromagnetic waves by a sharp probe that is coupled via near-field interaction to the sample of interest. For small tip-sample distances, the near-field optical resolution and contrast clearly depend on the tip radius and the different sample properties only. Such a scenario may be easily modelled by the analytical dipole-approximation. Nevertheless, this simplified model suffers from limitations such as neglected retardation or the non-point-like tip, and thus is inappropriate to be applied to more complex systems including e.g. anisotropic substrates or structured samples. Hence, a full numerical description is needed to gain a deeper understanding of experimental results.

We present here simulations of the tip-sample interaction in a typical s-SNOM configuration. Our systems consist of a perfect electrically conducting sphere as the scattering and scanning tip, and various samples ranging from perfect electric conductors over typical dielectrics to anisotropic substrates. All calculations are performed using a classical finite element method (COMSOL).