Theoretical optimization and design of graphene-based multiple-band terahertz absorbers for sensing applications

In this paper, the metal-free absorber is implemented at terahertz (THz) frequency for the generation of multiband resonance peaks. The absorber is designed by introducing a semicircle notch and rectangle slot in a graphite sheet. The effect of the dimension of notches and slots is analyzed in detail to select the appropriate dimension of the absorber. It is found that a proposed absorber can generate multi-band resonance with higher absorption efficiency. By varying the dimension and thickness absorber can also provide merging and separation of resonance peaks. Further, the Polarization insensitivity of the proposed absorber is also studied for the wide range of incidence angle (θ) for both TE and TM modes. The performance sensitivity of the proposed absorber is analyzed to show its use in sensing devices.