Fabrication of a terahertz wave absorber based on dielectric spheres

A terahertz wave absorber composed of dielectric spheres is proposed. The proposed absorber offers advantages compared to other metamaterial-based absorbers owing to low-cost and flexibility of fabrication that strongly relaxes the constraints for the optical domain. The dielectric spheres composed of titanium oxide (TiO₂) are aligned with a hexagonal lattice on an aluminum substrate. The absorption over 90% is obtained at the frequencies of the Mie resonances of the spheres. Furthermore, as results from simulation, the performances of metamaterial based absorber are kept over a wide range of incident angles.