Light Scattering Nanoparticles: Plasmonic Resonances on Spheres and Regular Polyhedra Through the Theory of Characteristic Modes

The optical properties of nanoscatterers have generated increasing research interest due to the recent advances in nanotechnology. In particular, an interesting case of resonant nanoscatterers are the plasmonic nanostructures, i.e., particles able to support localized charge oscillations, known as surface plasmons [1]. The appearance of these resonances is highly influenced by the material and morphological characteristics. In this presentation we will focus on the theoretical study between two plasmonic nanopolyhedra, the hexahedron and the octahedron [2], highlighting their connection with the resonant spectrum of a plasmonic sphere. Key feature of the analysis is the implementation of the Theory of Characteristic Modes (TCM) for the case of plasmonic scatterers [2]. The results obtained reveal the existence of bright and dark resonant plasmonic modes, triggered by their particular morphological characteristics.

[1] U. Kreibig and M. Vollmer, Optical properties of metal clusters, vol. 25. Springer Science & Business Media, 2013.
[2] P. Ylä-Oijala, D. C. Tzarouchis, E. Raninen, and A. Sihvola, “Characteristic Mode Analysis of Plasmonic Nanoantennas,” IEEE Trans. Antennas Propag., vol. 65, no. 5, pp. 2165–2172, May 2017.