Triple-Band Terahertz Perfect Light Absorber Using the Strong Interaction of Two Metallic Resonators

摘要

An approach to realize a multiple-band perfect light absorber is demonstrated using a simple metamaterial design featuring a composite metallic structure consisting of a closed ring and a rectangular patch atop a metallic substrate separated by an insulator. Three narrow-band and discrete resonance peaks with nearly 100% absorption rates are obtained. The first absorption peak is due to the dipole resonance of the closed ring, while the last two absorption peaks are caused by the coupling effect of the closed ring and rectangular patch. The field distribution of the three absorption peaks is given to provide additional evidence. Unlike traditional multiple-band light absorbers that eliminate (or avoid) the interaction between the metallic array structures, our design is based on the mode coupling of the composite structure. This method can obviously reduce the number of metallic resonators, simplify the structure design and reduce fabrication costs.