Modeling array of eccentric core-shell plasmonic spheres

Summary form only given. Core-shell spheres have attracted significant interests in metamaterial community. Basically combination of a positive permittivity dielectric and a negative permittivity plasmonic material not only can control the resonances but also the effective material permittivity locally. This means one can use an array of coreshell spheres where, for instance, each has a different core size and as such tailor a desired material property across the array. Basically, any material can be engineered with core-shell spheres made from only two materials (the main concept of digital metamaterial).While the concept is very promising the computation is very challenging. This is due to the having a large finite array of different core-shells of dispersive materials and the fact that they can be located very close to each other. This will face us a broad-spectrum eigenvalue problem which makes simulation based on numerical methods very challenging, if not impossible. We need to add to these the cases which core-shells have eccentric geometries either due to the requirement to achieve a physic of interest or the fabrication practicality. In present work, an analytical solution for the problem of scattering by a cluster of eccentric core-shell spheres is demonstrated. Full wave multipole expansion method is applied to express the electromagnetic fields in terms of the electric and magnetic dipole modes and the higher order moments. Addition theorems will be implemented to expand fields in desired coordinate systems and to apply boundary conditions successfully. The solution of large array of eccentric plasmonic and dielectric core-shell spheres is determined, and unique physics in the area of metamaterials, changing the element configuration, is described. Novel applications will be highlighted. Associated mathematics and speed and memory improvements for the problems investigated will be discussed.