The Optical Properties of a Truncated Spherical Cavity Embedded in Gold

A. Pors[1], O. Albrektsen[2], S.I. Bozhevolnyi[2], and M. Willatzen[1]
[1]Mads Clausen Institute, University of Southern Denmark, Sønderborg, Denmark
[2]Institute of Sensors, Signals and Electrotechnics, University of Southern Denmark, Odense, Denmark

The use of plasmonic effects to dramatically enhance the electromagnetic field near the surface of a metallic nanostructured surface has grown into a large research area in the effort to take advantage of the surface enhanced field. In this paper the electromagnetic field near a nano-sized truncated spherical cavity embedded in a gold substrate is investigated and modeled in 3D with COMSOL Multiphysics®. The simulated near-field is interpreted on the basis of Mie-theory and resonance of Localized Surface Plasmon polaritons (LSP). The optical properties, such as absorption and scattering of light, of the truncated spherical cavity are also investigated. It is found that LSP resonances mainly affect the scattering, which is due to the spatial shape of the LSPs.