Local density of states near spatially dispersive nanospheres

Abstract

We construct the dyadic Green function of the electromagnetic field in the presence of a spatially dispersive spherical object. It contains all the information on light-scattering processes off a spatially dispersive sphere, and, in particular, its imaginary part gives the local density of states. Our construction of the Green function automatically yields a dispersion relation for surface polaritons in terms of surface impedances. From a methodological point of view, our approach is based on the extinction theorem and Huygens' principle. This allows for the straightforward application of Maxwell boundary conditions, without the need to resort to so-called additional boundary conditions. With this, we investigate the influence of spatial dispersion on the local density of states in the proximity of a nanosphere.