Wideband terahertz absorber based on the coupling of the double ellipse de-overlapping and I-shaped structure

Abstract

In this letter, a wideband terahertz absorber based on a double ellipse de-overlapping and an I-shaped structure is presented. Its structure unit is a typical metal-medium-metal structure, the top metal is composed of a double ellipse de-overlapping and the central layer of an I-shaped structure, and the bottom layer is also a double ellipse de-overlapping. Broadband absorption is achieved by adjusting the structural parameters of the unit, equivalent circuit model is used to evaluate the resonant frequencies of different absorption peaks. The operation frequencies of the absorber can be extended from 5.5 THz to about 1.2 THz. The operation bandwidth of terahertz waves decreases from close to 2 THz to about 0.5 THz by adjusting the structural parameters of the unit. The device demonstrates excellent broadband absorption ability at various incidence angles, exhibiting strong angular stability. The wideband terahertz absorber can be used in terahertz communication, terahertz imaging, terahertz sensing, and other fields.