Dependence of transmittance and group index on the coupling strength between constituents of a metamaterial

Abstract

Recent studies on the coupling effects between constituent elements of metamaterials have opened up a new gateway to many fascinating electromagnetic properties and functionalities that cannot be explained by the uncoupled point of view. In this work, we numerically investigated, in a THz regime, the coupling between a cut wire and a split-ring resonator, which gives rise to an interesting phenomenon?the so-called electromagnetically induced transparency-like effect. The trade-off between the maximum transmittance of the transmission window and the group index, which depends on the coupling strength between constituent elements, was systematically studied. Furthermore, by characterizing this trade-off by the transmittance-delay product (figure of merit), a criterion for slow-light applications was provided.