Efficiency tunable broadband terahertz graphene metasurface for circular polarization anomalous reflection and plane focusing effect

In this paper, a broadband reflective metasurface (MS) with patterned graphene is proposed and investigated numerically, which can realize wavefront manipulation dynamically in terahertz (THz) region. The unit-cell of the proposed reflective MS is composed of a dielectric substrate sandwiched with a single layer oval-hollow -structure (OHS) graphene and a metal ground-plane, which can achieve the cross-polarization conversion of the circularly polarized (CP) waves in reflection mode. The full 2 pi phase shifts of the reflected orthogonal CP wave can be obtained by changing the orientation angle of the OHS graphene in a broadband frequency range with different Fermi energy level (EF). Moreover, it has been verified that the reflection CP conversion efficiency is highly dependent on the variation of the EF. In particular, the efficiencies of the anomalous reflection and focusing effect of the reflective MS can be adjusted dynamically by changing EF. It has great prospects in the THz application fields such as communication and imaging.

Automated summary

In this paper, a broadband reflective metasurface (MS) with patterned graphene is proposed and numerically investigated for wavefront manipulation in the terahertz (THz) region. The unit-cell of the proposed reflective MS consists of a dielectric substrate, a single layer oval-hollow-structure (OHS) graphene, and a metal ground-plane, enabling cross-polarization conversion of circularly polarized (CP) waves in reflection mode. By changing the orientation angle of the OHS graphene, full 2 pi phase shifts of the reflected orthogonal CP wave can be achieved over a broadband frequency range with different Fermi energy levels (EF). Furthermore, the efficiency of reflection CP conversion is highly dependent on EF variation. Particularly, the efficiency of anomalous reflection and focusing effect of the reflective MS can be dynamically adjusted by changing EF. It has great prospects in THz applications such as communication and imaging.