Near Infrared Perfect Absorber Based on Phosphorene-Gold Nano-Grating Surface Plasmon Resonance

Optical absorbers are widely utilized in plasmonic sensors, optical switch, and solar-cells due to their effectiveness in capturing electromagnetic radiation. Furthermore, these devices can be tailored to optimize absorption at particular wavelengths within the mid-infrared spectrum. In this study, a perfect optical absorber was designed which included a Silica substrate with di-electric nano rode which is doped in Silica, Gold grating, a phosphorene layer which is cover structure. The effects of coupling between the nanorod and gold grating were investigated using the finite element method. The results indicate that, within the designed structure, the placement of the nanorod in the substrate significantly enhances absorption to more than 98% and the independence of absorbance from the thickness of phosphorene (i.e. less than 0.1% variation in the absorption). This perfect absorber operates over a narrow absorption range of 4 to 16 nm which is a good candidate to optical filters.