Filling the THz Gap

Abstract

APPLIED PHYSICS At frequencies below a few hundred GHz, electrons are the information carriers of choice. For frequencies above a few THz, including infrared, the visible, and ultraviolet wavelengths, optical technologies prevail. The frequency range in between is referred to as the THz gap. Natural materials do not show much response in this gap range, even though there are many expected applications in the areas of biosensing, imaging, communication, and security. To help fill this gap, Tao et al. present a metamaterial—an artificial structure in which the electromagnetic response can be engineered by design—which has a strong response in the THz regime. By engineering a bilayer structure comprising a composite of metallic split-ring resonators, wires, and a polyimide spacer, they show that the electric permittivity and magnetic susceptibility response can be tuned separately. Such designed materials illustrate the potential of accessing a frequency range normally inaccessible to natural materials. — ISO Opt. Express 16 , 7181 (2008).