Quad-band perfect absorption of the terahertz light using the simple metamaterial resonator

Abstract

Multiple-band light absorbers have been proved to have important applications in many fields. The structures of them, however, usually require multiple different dimensions of sub-units, which will inevitably lead to time-consuming optimization and complex manufacturing processes. Herein, we show that simple metamaterial design (analogous to a modified T-shaped resonator) can be utilized to achieve quad-band absorption at terahertz frequency. The structure possesses the ability to concentrate the incident wave around the resonator using the localized resonance responses. Four clearly distinguishable absorption peaks with narrow bandwidth and near perfect absorption are realized. Moreover, the number of absorption peaks can be controlled from the original quad-band to triple-band, dual-band and even single-band by varying some specific parameters. Multiple-band device with advantages of simple structure design and controllable absorption peak number is promising in practical applications.