Lithographic fabrication and spectroscopic characterization of a THz metamaterial adsorber

Abstract

THz metamaterial absorbers are often studied by computational techniques, where the influence of actual material parameters and fabricating limitation has not been completely understood. Here we present an experimental investigation on a far-infrared metamaterial absorber composed of a gold disk-shaped resonator, a silicon oxide spacer, and a gold film. The samples are fabricated using the UV laser lithography technique in combination with the clectron-beam evaporation. The absorption fcature of fabricated samples is examined by Fourier-transformmed infrared spectroscopy and supported by finite integration simulations. By tuning the periodicity between meta unit-cell, it is demonstrated that the total absorptivity can be tuned up to 96 % at 58 THz. The finding results confirm earlier prediction on the unique absorption behavior of metamaterials in the THz regime.