Nanolayered graphene-based tunable terahertz metasurfaces as polarization converters and beam deflectors

Abstract

This paper proposes a graphene-based tunable terahertz (THz) metasurface for simultaneous linear polarization conversion and beam deflection. The designed unit cell structure consists of a hybrid graphene-gold array and a reflective metal film separated by SiO2 spacer, which is a typical sandwich resonance model. When the x-polarized wave is vertically incident, the designed system can be regarded as a broadband polarization converter with a bandwidth of 1.2 THz, where efficiency exceeds 90%. By changing the Fermi level of graphene, the bandwidth of the PCR spectrum can be effectively adjusted, thus realizing active tunability. By introducing principle of geometric phase, it is proved that the proposed design is effective in beam deflection. In addition, with the change of the incident angle, the PCR spectrum can still maintain good performance. Therefore, the proposed design can be effectively applied to next-generation integrated communication systems.