Dresden 2017 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 59: Plasmonics and Nanooptics

O 59.22: Poster

Dienstag, 21. März 2017, 18:30–20:30, P2-OG1

Long-Lived Electron Emission Reveals Ultra-localized Plasmon Modes in Gold Nanosponges — •Germann Hergert¹, Jan Vogelsang¹, Felix Schwarz², Dong Wang², Heiko Kollmann¹, Petra Groß¹, Erich Runge², Peter Schaaf² und Christoph Lienau¹ — ¹1Carl von Ossietzky Universität, Oldenburg, Germany — ²2Technische Universität Ilmenau, Ilmenau, Germany

Materials with disorder on the nanometer scale are known to exhibit large field enhancement properties, making them viable for enhancing non-linear optical effects or for investigating quantum optical processes. Different 2D model systems have been used to study the role of disorder. Promising 3D models for this are nanoporous gold particles ("nanosponges") which have recently attracted attention as templates for surface-enhanced Raman sensing due to their multiple plasmon resonances from the visible to the NIR spectral range, a high surface-to-volume ratio, and a high density of catalytic sites [1].

Here we report the observation of long-lived, spatially highly localized plasmon states on the surface of nanosponges. Using a 16-fs excitation pulse at 1600nm wavelength, we measure light-induced electron emission from single sponges with lifetimes of several tens of fs. We observe the long-lived electron emission, as a nonlinear process with the exponent n=5-7. This in combination with optical extinction measurements and FDTD calculations, points to a strong coupling of the localized modes with the delocalized dipolar plasmon mode, resulting in an extraordinary high excitation efficiency of the hot spot resonances.

[1] Wang, D.; Schaaf, P. J. Mater. Chem. 2012, 22, 5344-5348