Metallic and dielectric resonators in broadband half-wave mirrors for terahertz frequencies

Metasurfaces provide the platform for a myriad of applications owing to exotic properties that are not commonly found in nature. Typically, metasurfaces are constructed using arrays of metallic or dielectric subwavelength resonators. In this paper, we compare two designs of broadband terahertz half-wave mirrors, namely a metallic and a dielectric resonator metasurface. Although both designs have different operational mechanisms, the fractional bandwidth achieved by both meta-surfaces is more than 67% with reflection efficiencies of greater than 80%.