Metasurface Broadband Solar Absorber.

Abul K Azad,Ting S Luk,Diego A R Dalvit,Nina R Weisse-Bernstein,Milan Sykora,Hou-Tong Chen,Wilton J M Kort-Kamp,Antoinette J Taylor

doi:10.1038/srep20347

Abstract

We demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure.

Highlights

Metamaterials have allowed the demonstration of many exotic electromagnetic phenomena and inspired some interesting potential applications[1]
There have been some demonstrations of material structures as high-performance solar absorbers, for instance, using dense nanorods and nanotube films[11,12], multilayer planar photonic structures[8,13,14], and photonic crystals[15]
Extending the absorption bandwidh of a solar absorber, covering entire visible and near-IR spectrum with a controllable cutoff wavelength for minimizing mid- and far-IR emmisivity, is highly desirable. Inspired by these earlier works, here we demonstrate the design, fabrication and characterization of a broadband wide-angle metasurface absorber exhibiting a solar weighted absorptance of 88% in the wavelength range 350nm – 1100nm, and less than 2% absorptance at wavelengths larger than 1500 nm

Summary

Introduction

Metamaterials have allowed the demonstration of many exotic electromagnetic phenomena and inspired some interesting potential applications[1]. The measured absorptance at 20° angle of incidence is shown, for both s- and p-polarizations, confirming the polarization-independent high absorption over almost the entire solar spectrum.

Results

Conclusion