Berlin 2015 – scientific programme
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O: Fachverband Oberflächenphysik
O 75: Plasmonics and Nanooptics
O 75.9: Poster
Wednesday, March 18, 2015, 18:15–21:00, Poster A
Sphere-based Aperture SNOM: A tool for ultrafast nano-optics — •Michael Hartelt, Cristian González, Anna-Katharina Mahro, Daniela Bayer, Elena Ilin, Deirdre Kilbane, Stefan Mathias, Egbert Oesterschulze, and Martin Aeschlimann — Department of Physics and Research Center OPTIMAS, TU Kaiserslautern, Germany
In traditional aperture Scanning Near-field Optical Microscopy (a-SNOM), the sample is illuminated through a sub-wavelength sized aperture at the apex of a tapered fiber or an Al-coated SiO2 pyramid. These constructions have a number of drawbacks, such as the metal-metal interaction between tip and sample and the low transmission which causes problems for achieving the high intensities that are required for time-resolved measurements. We developed a new cantilever design, in which a SiO2-sphere was added at the apex of such a pyramid. Here, we demonstrate the various benefits of this design for the imaging of localized and propagating surface plasmons, as well as ultrafast pump-probe experiments with pulse lengths well below 100 fs. Illuminating with an Optical Parametric Oscillator (OPO) allows us to address a wide spectral range from the UV up to the infrared regime. A setup combining these components provides a versatile tool for the investigation of ultrafast phenomena in nano-optics.