Guiding and routing surface plasmons with transformation-invariant metamaterials

Abstract

Abstract Rough metallic surfaces cause severe scattering to surface plasmon polaritons (SPPs), thereby limiting SPP transmission efficiency. Here, we propose a general scheme to design ultracompact plasmonic routers that can confine and guide SPPs on an arbitrarily shaped rough surface. Our strategy makes use of recently proposed transformation-invariant metamaterials (TIMs). To illustrate the advantages of this approach, we perform finite-element simulations, showing that the performance of the designed surface wave router is robust against the change in thickness. As a result, a λ/6 thick TIM layer can significantly suppress scattering from arbitrarily shaped metallic bumps or crevices. We also give a blueprint to implement such ultracompact surface wave routers based on periodic metal/epsilon-near-zero material stackings.