Wide-angle broadband absorber based on one-dimensional metasurface in the visible region

A broadband absorber based on a one-dimensional metasurface is designed and characterized numerically. In this absorber, the lossless dielectric in non-noble metal nickel (Ni) grating grooves is essential, which supports strongly the localized electromagnetic modes concentrated in the nanocavity formed between two metallic walls. A high absorbance from 380 to 760 nm for either TM or TE polarization is attained. In particular, a nearly perfect absorbance (over 99%) is achieved at λ = 450 nm for TE polarization. Furthermore, the absorption in the visible region remains above 60% at incident angles up to 45° for the two polarizations.