Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 36: Poster Session II (Organic films and electronics, photoorganics; Nanostructures; Plasmonics and nanooptics, Surface chemical reactions and heterogeneous catalysis, Surface dynamics )
O 36.35: Poster
Dienstag, 12. März 2013, 18:15–21:45, Poster B2
Observing the localization of light in space and time by ultrafast second-harmonic microscopy — M. Mascheck1, S. Schmidt1, M. Silies1, T. Yatsui2, K. Kitamura2, M. Ohtsu2, •D. Leipold3, E. Runge3, and C. Lienau1 — 1Carl von Ossietzky Universität, Oldenburg, Germany — 2School of Engineering, University of Tokyo, Japan — 3Technische Universität Ilmenau, Germany
Anderson localization of light waves is notoriously hard to observe and controversially discussed for many decades. We present a method to investigate the degree of localization of the near-field of visible light in random arrays of vertically aligned ZnO nano-needles in space and time[1]. The second-harmonic emission of the needle array exhibits strong spatial fluctuations due to the presence of strong localization-induced hot-spots in the near-field intensity. We spatially resolve the second harmonic intensity with a tightly focused optical scanning-microscope setup.
In order to study the finite lifetime of the localized modes, the microscope is coupled to an interferometric frequency-resolved autocorrelation (IFRAC) setup. Combining both, the microscope focus and IFRAC with ultrashort laser pulses, we observe the localized light field with a spatial resolution better than 0.5µm and a temporal resolution better than 6 fs. We present measurements indicating hot-spot sizes smaller than the microscope resolution and mode lifetimes of 15 fs. In addition, 3D-FDTD calculations which are in well agreement with the experiment are presented[1].
[1] M. Mascheck et al., Nature Photonics 6, 293 (2012)