Nonlocal response of planar plasmonic layers

Nonlocal interactions of plasmonic nanostructures are currently being intensively investigated. It is generally accepted that nonlocal interactions are most pronounced on structures with nanometer unit sizes and affect the shape of spectral functions of characterizing quantities in the resonance region. Numerical analysis of nonlocal phenomena is very complicated and it is advantageous to use it for the analysis of geometrically more complex structures. For some simple structures it is possible to find analytical solutions which can then be used, among other purposes, to build semi-analytical approaches for the analysis of some more complex structures. This article is focused on the efficient description of nonlocal manifestations of the planar plasmonic layers using a hydrodynamic model. The originality is particulary focused on the extension from the single nonlocal layer towards the more general case of two adjacent nonlocal layers (bilayers). The results for both single layer and bilayer case are presented and discussed in detail. Also, one of the here presented important technical results is the novel presentation of the transfer matrices for the nonzero normal component of the current densities at the interfaces of the plasmonic layer.