Berlin 2012 – scientific programme
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O: Fachverband Oberflächenphysik
O 3: Plasmonics and nanooptics I
O 3.2: Talk
Monday, March 26, 2012, 10:45–11:00, MA 005
Enhancement of non-linear effects using nano-wires — •Woyten Tielesch1, Mathieu Gentile1, Mario Hentschel2, Harald Giessen2, and Manfred Fiebig3 — 1HISKP, Universität Bonn, Germany — 24. Physikalisches Institut and Research Center SCoPE, Universität Stuttgart, Germany — 3Departement of Materials, ETH Zürich, Switzerland
Gold nano-wires are artificial sub-wavelength materials with tailored optical properties. Experimental and theoretical investigations show amplified local fields on the nanoscale. In a non-linear material this makes nano-wires act as an optical catalyst. We present a method using such a catalyst to enhance non-linear functionality of a given material.
Our sample consists of fields of regularly spaced gold nano-wires on a Cr2O3 substrate. Cr2O3 shows second-harmonic generation (SHG) for incident light peaked around 1.05 eV and has been intensively characterized for reference. Accordingly, the wires have linear resonances between 0.9 eV and 1.5 eV. In our experiment we use amplified 120 fs laser pulses to investigate the influence of the wires on the SHG spectrum of the substrate. Fundamental wavelengths from 0.8 eV to 1.1 eV are used.
A significant modification of SHG due to the wires is observed. We demonstrate that the spectral profile of the SHG signal is strongly correlated to the linear spectrum of the wires. In addition, we show that a strong signal occurs in a direction where the bare substrate shows no signal at all, a fact still requiring theoretical explanation.