Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 71: Poster: Plasmonics and Nanooptics
O 71.10: Poster
Mittwoch, 20. März 2024, 18:00–20:00, Poster D
s-SNOM calibration using multiple tapping harmonics for complex permittivity reconstruction — •Dario Siebenkotten1, Bernd Kästner1, Arne Hoehl1, Manuel Marschall1, and Shuhei Amakawa2 — 1Physikalisch-Technische Bundesanstalt, Abbestr. 2-12 10587 Berlin — 2Graduate School of Advanced Science and Engineering, Hiroshima University, Higashihiroshima, Japan
Infrared scattering-type scanning near-field optical microscopy (s-SNOM) has found wide-spread success in the nanoscale investigation of material properties such as the free-carrier density and crystal structure.
The deep sub-wavelength resolution of s-SNOM is achieved by the interaction between the sharp apex of a metallized AFM tip under illumination and the sample surface below it. This complex system poses a difficult inverse problem for the recovery of sample properties from measurements.
Recently, a calibration method has been proposed that describes this interaction by means of calibration parameters, instead of fitting the physical characteristics of a heavily idealized tip model [1].
However, the proposed calibration model was designed for a stationary tip, but the use of periodic tip height modulation is essential for s-SNOM measurements. Here, we propose an extension to the model that includes the tip modulation by making use of multiple tapping harmonics. We validate our proposed extension on doped silicon microstructures by reconstructing the permittivity over a broad spectral range and extracting the free-electron density and damping.
[1] Guo et al. Appl. Phys. Lett. 118, 041103 (2021)