Regensburg 2010 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 53: Plasmonics and Nanooptics IV
O 53.4: Vortrag
Mittwoch, 24. März 2010, 15:45–16:00, H32
Scattering near-field microscopy in the THz with a free-electron laser — •Hans-Georg von Ribbeck1,2, Marc Tobias Wenzel1, Rainer Jacob2, and Lukas M. Eng1 — 1Institut für Angewandte Photophysik, TU Dresden, 01062 Dresden, Germany — 2Institut für Ionenstrahlphysik und Materialforschung, Forschungszentrum Dresden - Rossendorf, 01314 Dresden
We present scattering-type scanning near-field optical microspectroscopy (s-SNOM) invstigations, successfully operated in the THz range with a wavelength independent spatial resolution of 150 nm. Our microscopy set-up bases on a true noncontact atomic force microscope (nc-AFM) combined with the free-electron laser (FEL) source at the Forschungszentrum Dresden-Rossendorf. This laser provides tunability from 30 - 250 um. We were able to record, for the first time ever, s-SNOM signatures with a FEL at wavelengths ranging from 30 um to 180 um (10 - 1.67 THz). In addition to the near-field dependent optical signals we also demonstrate the imaging capabilities of our THz-s-SNOM. Image scans were performed on a specially designed test structure consisting of a topography-free composite of a polymer/gold sample. On such samples, topography independent strong optical material contrast could be demonstrated at 150 um wavelength. We achieve a resolution of better than 150 nm corresponding to better than l/1000.