A Tunable Dual-Band Terahertz Metasurface Based on Dirac Semimetal

In this article, a tunable terahertz metasurface based on Dirac semimetal thin films (DSF) is proposed. By adjusting theslot position of a DSF-based split-ring resonator (SRRs), the structure can realize the switching between wave absorption and polarization conversion. In absorption state, the structure operates at 0.4-1.0THz. In polarization conversion state, the design converts linearly polarized waves to circularly polarized waves at 0.4-1.2 THz. Dirac semimetal enables a dynamically adjustment of polarization conversion performance by changing its Fermi energy level. Simultaneous wide-angle stability of up to 60° reveals that the same performance can be maintained at larger incidence angles. The simple structure of the converter is suitable for terahertz sensing, dual link satellite communication and imaging.