Open Access01–20 THz ultra-broadband perfect absorber via a flat multi-layer structure
Author(s) -
Gongjie Xu,
Jun Zhang,
Xiaofei Zang,
Okihiro Sugihara,
Hongwei Zhao,
Bin Cai
Publication year - 2016
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.24.023177
Subject(s) - materials science , anti reflective coating , refractive index , optics , absorption (acoustics) , broadband , optoelectronics , substrate (aquarium) , terahertz radiation , layer (electronics) , dopant , silicon , polystyrene , doping , nanotechnology , composite material , oceanography , physics , geology , polymer
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 TiO 2 nanoparticle 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.