Terahertz Biosensor with Polarization-Insensitive Properties Based on Metal Metasurface

This paper presents a terahertz biosensor with polarization-insensitive properties based on metal metasurface. The biosensor is a five-layer structure with a resonant structure consisting of four open resonant rings in a symmetric structure, which enhances the contact of electromagnetic waves with the analyte through a reflective layer. Simulation results show that the biosensor produces 99.9% absorption peaks in the range of 0.4-0.9 THz with a sensitivity of 0.225 THz/RIU. The designed structure with polarization-insensitive characteristics has potential applications in the field of nondestructive, rapid and label-free detection.