Two-in-one terahertz metasurface: a widely adjustable narrowband perfect absorber and a highly sensitive biosensor
摘要
A dual-function terahertz metasurface is designed under idealized (noise-free, lossless) simulation conditions based on a copper-based resonator. The meta-structure serves not only as a perfect narrowband absorber but also as a highly sensitive refractive index sensor for analytes. The proposed meta-structure features a compact, ultrathin, simple, single-material design based on a periodic array of circular rings and disks. A near-perfect absorption of 99.99% is demonstrated at the resonant frequency of 0.8 THz, which can be configured over the span of 0.53–1.47 THz via geometric parameters and dielectric permittivity adjustments. The meta-absorber design is confirmed to be polarization-insensitive and also wide-angle, preserving the absorption