Ultra-broadband metamaterial absorber in the visible and near-infrared range based on silicon carbide hemisphere arrays

In this paper, we theoretically study the broadband optical metamaterial absorber composed of silicon carbide (SiC) hemisphere array placed atop a tungsten substrate, where high average absorptivity reaching 93.5% is obtained in a broad range from ultraviolet to near-infrared frequency. The presented broadband metamaterial absorber exhibits good tolerance to incidence angle up to 40 and shows polarization-independent performance. The underlying mechanism of the broadband absorption is attributed to the magnetic dipole resonance stimulated inside SiC hemispheres as well as the intense field trapping caused by lattice resonances. The presented structure is simple and efficient, and also offers promising applications in broadband thermophotovoltaic devices.