Broadened band near-perfect absorber based on amorphous silicon metasurface

A dielectric broadened band near-perfect absorber based on an amorphous silicon(a-Si) T-shaped nanostructure metasurface is investigated numerically and experimentally. The simultaneous suppressed transmission and reflection of the a-Si nanostructure metasurface are achieved by investigating the interference of the periodically adjustable electric dipole(ED) and magnetic dipole(MD) Mie resonances. The absorption of the a-Si nanostructure metasurface approaches the maximum of 95% in simulation and 80% in experiment with a top-hat shape in the spectral range from 580 nm to 620 nm by employing the T-shaped nanostructure. The proposed near-perfect absorber provides a new approach for expanding absorption bandwidth by integrating different nanostructures in metasurface, which is potentially applicable in nanophotonic fields of optical isolation, optical trapping and energy harvesting.