Five Layer Bi-Directionally Adjustable Perfect Metamaterial Absorber Based on Silver Gratings with Four Narrow Bands and 1650 Nm Broadband Absorptions

Abstract

In recent years, the exceptional performance of metamaterial perfect absorbers in applications such as solar cells, sensors, and photoconversion devices has highlighted their crucial role in various scientific and technological domains. However, the design of perfect absorbers that can achieve both narrowband and broadband absorption using relatively simple structures continues to pose a significant challenge. This study presents a bidirectional metamaterial perfect absorber that is based on a silver grating and features a specialized structure engineered to achieve both broadband and multi-narrowband perfect absorption simultaneously. When the light source is incident from above, four distinct absorption peaks are observable within the near-infrared wavelength range, with absorptivity values of 91.8%, 99.8%, 94.3%, and 93.2%, all of which have demonstrated effective sensing performance. Conversely, when the light source is incident from below, broadband absorption is realized across the wavelength range of 650 to 2300 nm, yielding an average absorption value of 95.85% that is largely insensitive to the angle of incidence. Furthermore, the resonance peaks of absorption can be tuned both simultaneously and independently by varying the parameters of the structural materials. Simulation results indicate that the designed absorber exhibits excellent narrowband and broadband absorption properties and is simpler and more straightforward to fabricate than alternative bidirectional absorber materials, suggesting its potential for broader applications relative to traditional absorbers.

Keywords: bidirectional functionality, gratings, metamaterials, Perfect absorption, plasma resonance