Numerical Analysis of Ultra-broadband Metamaterial Absorber with High Absorption in the Visible and Infrared Regions

Ultra-broadband and high absorption properties are significant for energy harvesting, solar cells, fire detection and imaging. An ultra-broadband and high absorption metamaterial absorber is proposed, which consists of a grid structure and a SiO2 rectangular structure. The simulation results of the metamaterial absorber show that the absorber has an absorption rate of more than 90% with a bandwidth of 3815 nm centered at about 2045 nm. Due to the asymmetry of the absorber structure, it is sensitive to the polarization angle, but still has certain polarization independence and wide-angle absorption characteristics in the whole band (300 ~ 4000 nm). The analysis shows that surface plasmon resonance, local surface plasmon resonance, cavity resonance, and coupling between resonant modes play a dominant role in the broadband and absorption of the absorber. The absorber with broadband and high absorption performance has great potential for solar energy harvesting, thermoelectric, and thermal emitter applications.