Design and analysis of a broadband metamaterial absorber applied to visible light band

Abstract

In this paper, a broadband metamaterial absorber (MA) operated in the visible light band with ultra wide-angle and polarization-insensitive characteristics which consists of a four-layer periodic structure is presented and analyzed, materials of the structure are tungsten, silicon dioxide, silicon nitride and silicon, respectively. According to numerical calculation analysis from finite-difference time-domain method, an absorptivity more than 96% and an average absorptivity of 99.1% are exhibited on this proposed MA. Furthermore, the MA shows not only preferably polarization-independent property through adjusting polarization angle from 0° to 90°, but also better wide-angle characteristics for both TE and TM modes. The MA's physical absorption mechanism which is generated by the coupling of dipole resonance and surface plasmon polaritons is analyzed by the electric and magnetic field distributions on the section plane. The influence for absorption from structure parameters is also investigated and construed. Finally, the equivalent circuit is drawn at the end of this article. The presented absorber has the potential to be applied in solar energy collection, light-to-heat conversion and other applications.