Near- and Mid- Infrared Quintuple-Band Plasmonic Metamaterial Absorber

In nanophotonic devices, the absorption of electromagnetic waves plays a critical role. Attempting to achieve narrowband absorption with multiple operating wavelengths, particularly in the near- and mid-infrared regions, is still a challenging endeavor. In this study, we developed a plasmonic metamaterial absorber (PMA) with a quintuple-band design. This PMA uses a periodic structure consisting of a dielectric layer sandwiched between a metallic nanobar array and a thin Ag film. The PMA can operate in both the near-infrared and mid-infrared regions. The absorptance of the proposed PMA for modes 1–5 is 98.02%, 99.47% 98.02%, 99.47%, and 96.09%, respectively. The high absorptance is due to hybridization of localized gap, cavity and surface plasmon resonance. This phenomenon can be explained by an inductance and capacitance circuit model. We also investigated the effects of structure parameters on the absorptance spectrum, which will provide valuable guidance for designing high-performance PMA.