Resonance and Sensing Properties of Single-Walled Carbon Nanotube Terahertz Metasurface

In this study, we extracted key parameters such as dielectric constant, conductivity, and refractive index from THz time-domain spectra of single-walled carbon nanotubes (CNTs) film. We propose a novel THz metasurface sensor characterized by etching a subwavelength array onto a single-walled CNT film. Both experimental and simulation results show that the metasurface device has pronounced resonance transmission enhancements at 0.727 and 0.914 THz. Furthermore, this novel terahertz (THz) metasurface for refractive index sensing has a maximum sensitivity of 423 GHz/RIU. The Fano model is employed to elucidate the resonance peak at 0.914 THz. Then, the physical mechanism of resonant transmission peak has been investigated according to multiple scattering theory, revealing that both resonance peaks are predominantly influenced by toroidal dipole. This research provides a practical solution for achieving heightened sensitivity in THz sensors, emphasizing the potential of the proposed metasurface device in advancing sensing technologies.