Ultra-wideband terahertz absorber based on graphene modulation.

Here we propose an ultra-wideband terahertz absorber (UWTA), which is composed of substrate, dielectric, and five-layer graphenes. By changing the chemical potential of graphene, the absorption coefficient of UWTA is larger than 0.9 from 1.51–8.25 THz. The absorption bandwidth is 6.74 THz. The relative bandwidth is 138.1%, and the modulation depth is 78.7%. Meanwhile, the number of each layer of graphene can be adjusted to achieve high absorption bandwidth, relative bandwidth, and modulation depth. Besides, due to the tunable chemical potential of graphene, the absorption coefficient can be adjusted to make up the manufacturing error.