Metasurface Perfect Absorber With Wide Frequency Tunability for Smart Terahertz Applications

This work presents a near-unity narrowband metasurface absorber (MSA) with an absorptivity (A(f)) of 99.1% at 4.74 THz. The MSA covers a spectrum from 4.68 to 4.8 THz (2.53%) with an A(f) ≥ 90%. DC biasing of graphene sheets leads to excellent tenability from 2.7 to 6 THz (3.3 THz). The narrowband A(f) over a wide THz range helps suppress electromagnetic interference in the desired band. The MSA is polarization-insensitive and works well for wide-incidence angles. The metasurface is compact and ultra-thin, making it a suitable candidate for smart THz applications.