Regensburg 2019 – scientific programme

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O: Fachverband Oberflächenphysik

O 12: Nanostructures at Surfaces II: Designer Structures and Surfaces

O 12.8: Talk

Monday, April 1, 2019, 17:00–17:15, H15

Revealing the influence of structural disorder in plasmonic systems — •Ediz Herkert, Florian Sterl, Steffen Both, Thomas Weiss, and Harald Giessen — 4th Physics Institute and Research Center SCoPE, University of Stuttgart, Pfaffenwaldring 57, 70569, Stuttgart, Germany

In the vast majority of studies, ensembles of plasmonic nanostructures are modeled as identical particles arranged in a perfectly periodic fashion. Several algorithms can efficiently calculate the optical response of these ideal systems. However, in all experiments structural disorder is present due to imperfections in the manufacturing process. This disorder is in fact expected to influence the optical properties. We investigate how disorder affects the optical response and how by the same token disorder can be utilized to tune the optical properties of the plasmonic ensemble. To this end, we define parameters that allow us to control the correlation and randomness of the structures and implement a coupled dipole model to compute the far-field response of any configuration of nanostructures. We validate these simulations with a microscopy setup that provides spectrally resolved real- and Fourier-space images of the plasmonic systems. Based on this data we explore the correlations between the disorder parameters and the optical spectra as well as the optical color appearance. Eventually, we aim to deduce the microscopic structural disorder solely from the measured far-field optical response of the plasmonic structures and tailor ab initio the bidirectional reflection distribution function.