Ultra-broadband wide-angle terahertz absorber realized by a doped silicon metamaterial

Abstract

Metamaterial absorber as a functional device has been extensively studied in the past decade, and its performance is continuously improved. Here we present a wide-angle terahertz absorber through polarization-insensitive doped silicon. The structural unit cell consists of a square silicon ring and a silicon substrate. Full-wave simulated results show that the designed absorber has excellent performance in the frequency range of 0.7–5.7 THz with the center frequency of 3.2 THz. The relative bandwidth ratio is 156.25% with absorptance greater than 90%. The design is insensitive to polarization at the small incident angle and still shows good performance over a wide range of incident angle. The proposed system may find potential applications in terahertz energy harvesting and thermal emission.