Scattering of surface plasmon polaritons at a planar interface by an embedded dielectric nanocube

We investigate scattering of surface plasmon polaritons (SPPs) at a planar metal-dielectric interface by a dielectric nanocube embedded in the metal layer using finite element method-based simulations. The scattering characteristics of the embedded nanocube, such as the scattering and absorption cross sections, far-field scattering patterns, reflectance, and transmittance, are calculated as functions of the wavelength of the incident SPP waves in the visible range. The main features of the characteristics are explained in connection with the excitation of plasmonic eigenmodes of the embedded nanocube. The most efficient scattering into waves propagating away from the metal surface, i.e., the radiating modes, occurs when a dipolar-like plasmonic mode is excited, whose eigenfrequency can be tuned by changing the edge length of the nanocube.