Plasmonics has become a dynamic and quickly expanding field of technology since the beginning of the last decade. The practical appeal of plasmons arises from their potential use as carriers of information. The speed of information processing has risen rapidly at the same time as electronic processing components have shrunk. An impediment to further progress is the limited speed of data transfer using electronic means. Optical data transfer is significantly faster but the required components are large relative to the most highly developed electronic processing components. Information transfer using surface plasmons may offer a way to bridge the gap. The field of research investigating plasmon-based technologies and devices is called plasmonics; many devices have been proposed and are under development, such as waveguides, resonators, antennae and lenses.

By making use of the extraordinary energy resolution and isochromaticity of the SESAM equipped with the MANDOLINE filter we are studying plasmonic properties in a great variety of metallic nanostructures. We investigate surface plasmon resonances in confined metallic systems experimentally by EFTEM and STEM-EELS, and theoretically by FEM, DDA and 3D-FDTD. The aim is to map near-field profiles of electromagnetic modes where particle plasmons, long-range wedge plasmons, slot void plasmons or toroidal void plasmons are identified. Using EFTEM the spatial distribution of resonant features can be directly imaged even in rather complex structures.