In this paper, a dual-band perfect absorber, composed of a periodically patterned elliptical nanodisk graphene structure and a metal ground plane spaced by a thin SiO₂ dielectric layer, is proposed and investigated. Numerical results reveal that the absorption spectrum of the graphene-based structure displays two perfect absorption peaks in the terahertz band, corresponding to the absorption value of $\text{99\%}$ at $35\mu m$ and $\text{97\%}$at $59\mu m$, respectively. And the resonance frequency of the absorber can be tunned by controlling the Fermi level of graphene layer. Further more, it is insensitive to the polarization and remains very high over a wide angular range of incidence around $\pm {60}^0$. Compared with the previous graphene dual-band perfect absorption, our absorber only has one shape which can greatly simplify the manufacturing process.

Active control of terahertz waves is critical to the development of terahertz devices. In this study, we investigated modulation property of terahertz wave based on the hybrid metamaterial/monolayer MoS₂/Si structure with tunable infrared light.

We demonstrate terahertz time-domain spectroscopy (THz-TDS) to be an accurate, rapid and scalable method to probe the interaction-induced Fermi velocity renormalization ν F ∗ of charge carriers in graphene. This allows the quantitative extraction of all electrical parameters (DC conductivity σ _DC , carrier density n , and carrier mobility µ ) of large-scale graphene films placed on arbitrary substrates via THz-TDS. Particularly relevant are substrates with low relative permittivity (< 5) such as polymeric films, where notable renormalization effects are observed even at relatively large carrier densities ( > 10 ¹² cm ⁻² , Fermi level > 0.1 eV). From an application point of view, the ability to rapidly and non-destructively quantify and map the electrical ( σ _DC , n, µ ) and electronic ( ν F ∗ ) properties of large-scale graphene on generic substrates is key to utilize this material in applications such as metrology, flexible electronics as well as to monitor graphene transfers using polymers as handling layers.