Numerical study of an ultra-broadband perfect absorber from ultraviolet to near-infrared based on metal quadruple staircase structure

We present and numerically investigate a novel ultra-broadband polarization independent and incident angle insensitive absorber via simulation. It has a high average absorption of 98.74% from 300 nm to 2000 nm, and the maximum absorption reaches 99.995% within the band. This high absorption is the result of three propagating and localized surface plasmon resonance modes. The absorption stays above 90% at 45 degrees incident angle, and above 80% at 60 degrees. Without heavily stacked alternating materials, the design can reduce fabrication complexities. The adjustability of the structural parameters is demonstrated by designing an absorber covering 200 nm to 3000 nm with over 90% absorption. This proposed device can have promising applications in solar energy harvesting, optical imaging, and optical communications.