Simulation of particle plasmons with the boundary element method

We plan to implement substrate effects for plasmonic nanoparticles within a boundary element method (BEM) approach based on the prescription of Garcia de Abajo and Howie [Phys. Rev. B 65, 115418 (2002)]. Our BEM software has been developed over the past few years and has been successfully used in cooperation with several experimental groups. A recent update now allows to simulate dielectric environments with several dielectric functions, and opens the possibility for the implementation of substrate effects. Different methodologies exist of how this could be done. In this project we plan to investigate the most promising route in close collaboration with Javier Garcia de Abajo (CSIC Madrid). Additionally, we will systematically investigate substrate effects in extreme light concentration and bio-sensing applications based on plasmonic nanoparticles. Both investigations will be performed in close collaboration with experimental groups. The main outcome of this project will be the development of a flexible simulation toolkit for plasmonic nanoparticles, which will be made available to a broader community after a careful testing stage.

Plasmonics deals with light confinement at the nanoscale. This is achieved by binding light to coherent electron oscillations at the boundary of metallic nanoparticles, the so-called surface plasmons. Surface plasmons come along with strongly localized electromagnetic fields, thus allowing for efficient light coupling to nanoscale quantum emitters such as molecules or semiconductor quantum dots. This research project has been concerned with the development of a simulaton toolbox for such plasmonic nanoparticles. In particular, we have extended the existing software such that now also metallic nanoparticles sitting on a substrate or some kind of layer structure can be simulated. The toolbox has been made available to the community on http://physik.uni-graz.at/mnpbem. In addition to the software developments, we have studied plasmonic field enhancements in numerous situations, mainly in collaboration with experimental groups. Particular highlights include nano patterning of surfaces through plasmonic light concentration as well as using electron microscopy for the measurement of the localized electromagnetic fields with nanometer resolution.