Broadband metasurface solar absorber in the visible and near-infrared region

We propose highly efficient and broadband metasurface absorber for 100 THz to 1000 THz frequency range. An array of pyramid shape block made up of tungsten material is placed above the dielectric layer to obtain metasurface behaviour in the absorber. A dielectric layer is used as a substrate to form a complete absorber structure. SiO2, SiN and GaAs are used as dielectric substrate and results obtained using different substrate materials are also compared. SiO2 substrate absorber is giving the best results among these three substrate materials. The absorber is numerically investigated with Finite element method (FEM). The proposed broadband absorber structure reported an average absorption of 79.67% in infrared and 93.7% in visible and 88.4% in all three regions (Infrared, Visible and Ultraviolet). It is also reported that geometrical parameters of structure control the absorption band. The absorber is flexibly tuned between low-frequency band to the high-frequency band which provides unique flexibility in design. The proposed broadband terahertz absorber can open a window for high-performance terahertz devices. The proposed absorber is applicable in designing efficient solar cells.