A flexibly tunable six-narrowband near-infrared perfect absorber based on composite resonant structure

Abstract With the rapid advancement of nanotechnology, metamaterials--an exceptional class of composite materials--have emerged as a research hotspot in applications such as perfect absorbers, optical stealth, and holographic imaging. Metamaterial perfect absorbers have garnered significant interest due to their compact dimensions and exceptional absorption efficiency. In this study, we design a multi-narrowband perfect absorber with a three-layer metal-dielectric-metal configuration using the FDTD method. Our proposed absorber structure consists of a Ag bottom layer, a Si dielectric layer and a Ag patterned layer from the bottom to top. This relatively simple structure realized six resonance absorption peaks at 1198 nm, 1231 nm, 1326 nm, 1387 nm, 1511 nm, and 1550 nm, with the corresponding absorption rates of 98.9%, 99.9%, 96.2%, 90.7%, 91.4%, and 99.3%, respectively. Furthermore, the absorber exhibits the flexibility to adjust the number of absorption peaks. Given its excellent performance, our proposed metamaterial absorber shows significant potential for a variety of applications, including photonic sensing, telecommunication systems, and light-controlled switching. As researches on metamaterials continue to advance, its range of applications is expected to expand further.