Broadband and Wide-Angle Terahertz Light Absorption in Doped Silicon Square-Hole Arrays
Abstract
A broadband and wide-angle polarization-insensitive absorber at the terahertz frequency is proposed and studied. The designed absorber consists of an antireflection film and a square-hole doped silicon array backed with a doped silicon substrate. Above 90% light absorption is achieved at frequencies of 0.86 THz to 4.29 THz, and such broadband absorption properties can be remained in a very wide range of incident angle. The distributions of electric field intensity at several neighbouring resonant frequencies are investigated to reveal the physical origin of this phenomenon. In the end, the effect of the structure dimensions on the absorption spectra is calculated and analyzed, so as to provide useful guidance for fabrication. We believe that our conclusions should be useful for the design of novel broadband and wide-angle polarization insensitive terahertz absorber.