Control of absorption properties of ultra-thin metal–insulator–metal metamaterial terahertz absorbers. (24th November 2020)

• Record Type: Journal Article
• Authors: Niu, Tianye; Qiu, Boqi; Zhang, Ya; Hirakawa, Kazuhiko
• Is Part Of: Japanese journal of applied physics. Volume 59:Number 12(2020)
• Publication Date: 2020-11-24
• Subjects: Metamaterial -- Terahertz -- Plasmonics -- Absorber -- Mode -- MEMS -- Metasurface; Physics -- Periodicals; 621.05
• DOI: 10.35848/1347-4065/abc925
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: We have systematically investigated the absorption spectra of ultra-thin metal–insulator–metal (MIM) metamaterial absorbers (MMAs) as a function of the insulator thickness, h . Absorption over 90% is obtained when h is optimized. Furthermore, we have found that, when the insulator thickness is increased, the resonance frequency first increases rapidly and, then, shows a gradual red-shift. As a result, the resonance frequency has a bell-shaped dependence on h . To explain the observed dependence, we provide an intuitive, analytical theory and show that the bell-shaped dispersion curve in the MIM MMA structure originates from the transition from the TM0 plasmonic mode to the vertical Fabry–Perot mode.