Large-area, omnidirectional metasurface exhibiting unpolarized broadband absorption

Abstract

Despite the ongoing efforts to design and fabricate large-area metasurface absorbers using cost-effective fabrication processes and low-cost materials, significant challenges persist. In this study, we present an anodized aluminum oxide template-assisted metasurface absorber with an area of 4 cm2, which incorporates glue cylinder arrays, a low-cost nickel layer, and protective glue layers. This device achieved an average absorptivity of approximately 91% (90% in the experiment) in the 200–900 nm wavelength range. The absorption level remained above 80% even at incident angles up to 45°, with calculated and experimental values of 92% and 82%, respectively. Moreover, the absorption is not sensitive to the thickness of the residual glue layers, making it ideal for roll-to-roll nanoimprinting processes. Therefore, the proposed metasurface absorber offers an alternative method for achieving broadband absorption in an effective manner and has great potential for related applications.