Active tuning of epsilon-near-zero point of hyperbolic metamaterial at visible and near-infrared regimes

Abstract

An active method of continuously tuning the effective permittivity of a hyperbolic metamaterial at visible and near-infrared spectra is introduced in this letter. A transparent conducting oxide, whose optical properties can be altered accurately by applying an external voltage, is inserted into a traditional metal–dielectric multilayer structure to increase the degree of freedom for tuning the epsilon-near-zero point by shifting the topological transition point. The tuning effect is explained in detail by combining the relationship between permittivity and voltage with wavevector analysis. This may promote other active applications of hyperbolic metamaterials and ultrafast tunable optoelectronic devices.