| Popis: |
In this chapter we present the possibility to engineer Fano resonances using multilayered hyperbolic metamaterials, either metal-dielectric or graphene-based multilayers. The proposed cavity designs are composed of multilayers with a central slanted part that allows the excitation of a propagative and an evanescent mode, the interference between these two modes being responsible for highly tunable resonances. The propagating mode can reach an extremely high effective index, making the realization of deeply subwavelength cavities possible, as small as 5 nm for visible light with a metal-dielectric multilayer, and 0.5 \(\upmu \)m in the terahertz regime with a graphene-based multilayer. The evanescent mode is rarely analyzed but plays an important role here, as its contribution determines the particular shape of the cavity characteristic. Moreover, these phenomena cannot be described using effective medium theory, and we provide a more rigorous analysis. The reported resonances are very sensitive to any structural changes, but also to small variations of the doping level for the graphene-based multilayers. |
