Hyperbolic metamaterials for utilizing epsilon-near-zero features

Abstract

In this study, we obtained epsilon-near-zero metamaterial at visible range by designing and fabricating a metal-dielectric multilayer anisotropic hyperbolic metamaterial. To do this, we experimentally characterize and extract the permittivity. We have used the epsilon-near-zero (ENZ) feature of hyperbolic metamaterial as a substrate to manipulate the resonance of plasmonic nanoantennas. We demonstrate that the vanishing index of the substrate slows down the resonance shift of the antenna, known as pinning effect. Moreover, we have controlled the pinning effect. Later, we show by optically pumping with fs pulses at a proper wavelength the ENZ point of the structure alters, in comparison to the linear case. The change in the effective permittivity happens in the order of unity, leading to ultrafast light-induced refractive index change. The localized surface plasmon resonance of metal nanoantenna is significantly influenced by the size, shape, and environment but also its substrate.