Channeling light along a chain of near-field coupled gold nanoparticles near a metallic film

We study the propagation of light along a chain of 20-nm-spaced gold particles lying onto a silica substrate in which a metallic film can be incorporated. We first discuss, for a pure dielectric substrate, the specificities of the chain modes as compared to larger separation distances where far-field coupling dominates. We then show how the introduction of a buried metallic film allows a substantial increase in the propagation lengths. Finally, we discuss the crosstalk between two adjacent chains, with and without the buried metallic layer, for applications to ultra-compact interconnects.