Surface Plasmon Resonances of Clustered Nanoparticles

Linear clusters made by tightly connecting two or more metallic nanoparticles have new types of surface plasmon resonances as compared with isolated nanoparticles. These new resonances are sensitive to the size of the junction and to the number of interconnected particles and are described by eigenmodes of a boundary integral equation. This formulation allows effective separation of geometric and shape contribution from electric properties of the constituents. Results for particles covered by a thin shell are also provided highlighting ultrasensitive sensing applications. The present analysis sheds a new light on the interpretation of recent experiments.