UV-visible broadband polarization-independent metamaterial absorber based on two-dimensional Au grating

A broadband metamaterial absorber (BMA) based on a thin metamaterial nanostructure consisting of 2D Au square grating on graphene-SiO2 film and Au substrate is proposed and designed. The optimized structure can achieve nearly perfect absorption with absorption of exceeding 90 % spanning a broad range from deep UV light to visible light (100 nm-700 nm). The excitation of Rayleigh anomaly (RA), cavity resonance (CR), surface plasmon polaritons (SPPs) and magnetic polaritons (MPs) are responsible for nearly perfect broadband ab-sorption, which have been analysed clearly by finite-difference time-domain (FDTD) method and the LC circuit model. Furthermore, the BMA is polarization and angle insensitive for incident light even at large angle. This proposed BMA not only has a simple geometry and ordinary metal-based material composition, but also shows a high performance in both bandwidth and absorptivity, suggesting that great potential in solar cell and photo -detector applications.

Automated summary

In this paper, a broadband metamaterial absorber (BMA) based on a thin metamaterial nanostructure composed of 2D Au square grating on graphene-SiO2 film and Au substrate is proposed and designed. The optimized structure achieves nearly perfect absorption in a broad range from deep UV light to visible light (100 nm-700 nm), exceeding 90% absorption. The mechanism responsible for the broadband absorption, including the excitation of Rayleigh anomaly (RA), cavity resonance (CR), surface plasmon polaritons (SPPs) and magnetic polaritons (MPs), has been analyzed using finite-difference time-domain (FDTD) method and the LC circuit model. The proposed BMA is also polarization and angle insensitive for incident light, even at large angles. It shows great potential in solar cell and photo-detector applications due to its simple geometry, ordinary metal-based material composition, and high performance in both bandwidth and absorptivity.