An anti-resonant hollow-core waveguide-based high-sensitivity fluidic sensor for terahertz applications

Abstract

In this work, we proposed an anti-resonant hollow-core waveguide fluidic sensor for terahertz applications. The waveguide was designed to be fully compatible with fused deposition modeling technique, thus enabling easy and low‑cost fabrication. The sensor integrates built-in fluidic channels to enable direct liquid analyte injection and efficient THz-analyte interaction. By utilizing the mode anti-crossing mechanism between the core-guided mode and the analyte-induced defect mode, a sharp loss peak appears in the transmission spectrum and shifts significantly with the analyte’s refractive index. The sensor achieves a high sensitivity of 206.7 GHz/RIU, nearly twice that of the state-of-the-art photonic bandgap waveguide-based THz fluidic sensors. Owing to the compact structure, low-cost fabrication, and high sensing sensitivity, the proposed antiresonant hollow-core waveguide sensor provides a promising solution for high-precision refractive index detection in chemical and biological applications.