Tunable narrowband terahertz multichannel filter based on one-dimensional graphene-dielectric photonic crystal

In this work, low terahertz (THz) spectroscopic properties of defective one-dimensional graphene-dielectric photonic crystal (1D-GPC) structure are theoretically investigated and analyzed in detail. The 1D-GPC is composed of a periodic stack of graphene nanolayers separated by isotropic dielectric slabs (SiO2), including an air defect as a central layer. The study is carried out using the well known transfer matrix method. Our numerical simulations showed that the suggested structure exhibits comb-like resonant peaks in the first transmission band of the 1D-GPC. These peaks are narrow, fully separated from each other and their number density increases by increasing the number of periods of the structure. Tunability of the optical characteristics of the device is also explored, taking into account the dependencies to the incidence angle, width, thickness, and refractive index of the dielectric layers, and the chemical potential of graphene sheets. Our calculations reveal that these transmission channels exhibit tunable behaviors against the parameters mentioned above. The observed spectroscopic features of the proposed structure make it an ideal candidate to realize tunable narrowband multichannel filters.