0.1-20 THz ultra-broadband perfect absorber via a flat multi-layer structure.
An ultra-broadband perfect absorber based on graded-index mechanism is designed and fabricated. The perfect absorber is comprised of a heavily-doped silicon absorption substrate and a flat six-layer antireflective structure. The refractive index of each layer was widely tuned by hollow polystyrene microsphere and TiO2nanoparticle dopants, which can offer a gradually changed refractive index profile from 1.3 to 2.9. The experimental results show that 98% absorption can be achieved within the range of 0.1-20 THz. Moreover, the high absorption efficiency as well as the ultra-broad range can maintain for incident angle from 0 to 75° by the theoretical simulation.
Gongjie
G
Xu
Jun
J
Zhang
Xiaofei
X
Zang
Okihiro
O
Sugihara
Hongwei
H
Zhao
Bin
B
Cai