Simulation of Realistically Shaped Nanoantennas Using COMSOL Multiphysics

C. Moosmann, G. Sigurdsson, K. Dopf, M. D. Wissert, H.-J. Eisler, and U. Lemmer
Light Technology Institute
Karlsruhe Institute of Technology
Karlsruhe, Germany

Nanoantennas – nanometer sized gold structures resonant at optical wavelengths have interesting properties for many applications. For numerical simulations of such structures simplified geometries are usually considered. However the fabricated shapes still differ significantly from perfect geometries and such structures are sensitive to geometrical changes. Here, we investigate how the deviation in geometry influences the measured results.

We use the RF-module of COMSOL for the calculation of scattering from nanoantennas. A method is presented, where the geometries from real nanoantennas are extracted from SEM images and a 3D CAD-model is built and imported into COMSOL. We compare realistically shaped to ideal geometries and show that significant differences occur in scattering response and near-field distribution.