Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 35: Poster Session I (Scanning probe methods)
O 35.18: Poster
Dienstag, 15. März 2011, 18:30–22:00, P3
Facts and artefacts in scattering scanning near-field optical microscopy. — •Anja Krysztofinski1, Marc Tobias Wenzel1, Rainer Jacob2, Hans-Georg von Ribbeck1, and Lukas M. Eng1 — 1Institut für Angewandte Photophysik, TU Dresden, 01062 Dresden, Germany — 2Institut für Ionenstrahlphysik und Materialforschung, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01314 Dresden, Germany
Scattering scanning near-field optical microscopy (s-SNOM) is a versatile tool for optically probing nanoscale systems in the visible and infrared wavelength range. In our setup, we used a He-Ne Laser with a wavelength of 633 nm for measurements in the visible and a CO2-Laser of 10.6 μm in the infrared range. To avoid misinterpretation of s-SNOM measurements, it is important to consider several kinds of artefacts that can affect the optical signal. Here, we present and classify the main types of artefacts that occur in s-SNOM measurements. Furthermore, artefacts are first theoretically described and then experimentally demonstrated. We focus on effects such as background scattering, geometrical topography artefacts, and feedback controller-induced effects. In addition, we will also present results on polarization effects and most importantly, optical contrast reversal as occurring for small nanoparticles. An important benefit of our set-up is the possibility to essentially avoid all such artefacts in order to obtain completely artefact-free results. For this purpose, we use higher harmonic demodulation, heterodyne interferometry and phase-locked-loop-based true-non-contact measurements in our s-SNOM set-up.