Tuning of terahertz metamaterials’ resonances via near field coupling

Abstract

Electromagnetic metamaterials (MMs) consisting of highly conducting sub-wavelength metallic resonators enable many unusual electromagnetic properties at designed frequencies which are not permissible with the naturally occurring materials. The electromagnetic properties of metamaterial are typically controlled by the clever design of the MM unit cell, often termed as meta-molecule, consisting of metallic split ring resonators (SRRs) or meta-atoms. The near field coupling between meta-atoms plays a vital role in tuning the natural resonances of individual SRR and, therefore, has the ability to modify the far-field radiation properties significantly. It is shown that near field coupling between the meta-atoms could lead to resonance tuning, mode splitting, and ultrafast switching in passive and active resonators. In this article, we present a brief review on tuning the metamaterial properties by active and passive manipulation of near field coupling between neighboring split ring resonators.