Tunable absorption in graphene-based hyperbolic metamaterials for mid-infrared range

Tunable absorption in periodic structure composed of graphene-based hyperbolic metamaterials (GHMMs) and isotropic medium is investigated by the transfer matrix method. The parallel part for relative permittivity of GHMMs consisting of monolayer graphene and conventional dielectric can be tuned by the chemical potential and dielectric layer thickness. The real part of the group index of GHMMs is insensitive to incident angle at the required frequency and the absorption of the periodic structure with GHMMs can be obtained nearly 100% at 22.4 terahertz (THz). The absorption peak of this frequency is almost uniform for both transverse electric (TE) and transverse magnetic (TE) polarizations. However, a new absorption peak can be observed incident angle is larger than 40 degree for TM polarization from 10 to 30 THz. The research results show that the absorption is insensitive to electromagnetic polarization at certain frequency. A new absorption peak can be found with TM polarization in low frequency region. These novel and effective GHMMs can replace metallic thin films as polarizing beam splitter for future optoelectronic applications.