Narrow band absorption and sensing properties of the THz metasurface based on single-walled carbon nanotubes

Abstract

Due to their excellent electrical and optical properties, carbon nanotubes have unique application prospects in the field of optoelectronics. This article uses vacuum self-assembly method to obtain an isotropic single-walled carbon nanotube film with a thickness of 2 μm from the dispersion of single-walled carbon nanotube powder through vacuum filtration; On the basis of extracting the dielectric parameters of the thin film in the range of 0.4 to 2.0 THz, a novel terahertz metasurface narrowband absorber based on single-walled carbon nanotube films was designed and prepared. This metasurface absorber is composed of square and I-shaped narrow slot resonators. The experimental and simulation results show that the proposed terahertz metasurface absorber exhibits four distinct resonance absorption peaks at 0.65, 0.85, 1.16, and 1.31 THz, achieving a perfect absorption of up to 90%. The absorption mechanism of this novel multi band terahertz metasurface was elucidated using the theory of multiple reflection interference. By setting analytical layers with different refractive indices on the surface of metasurface devices, the sensing performance of metasurfaces as refractive index sensors was deeply studied. The research results indicate that this new type of metasurface absorber has high sensitivity for refractive index sensing, providing new ideas and solutions for the further development of carbon-based new terahertz metasurface absorbers.