A hollow π-shaped all-metal terahertz metamaterial dual-frequency biosensor

A hollow π-shaped all-metal metamaterial sensor for terahertz detection has been developed in this paper. Unlike previous sandwich structures, the sensor uses a single metal material, making it simpler and more cost-effective. By analyzing the simulation result of the unit structure, it is found that the metamaterial exhibits high sensitivity with two distinct resonance peaks at 0.34THz and 0.57THz, refractive index sensitivities of 178.4GHz/RIU and 262.5GHz/RIU respectively, as well as figure of merit (FOM) values of 3.62 and 2.76 respectively. We use this all-metal metamaterial structure for biomolecular sensing by establishing a correlation between changes in resonance frequency and variations in biomolecular concentration. To validate its sensing performance, different concentrations of bovine serum albumin (BSA) solutions are prepared in this study. The lower limits of dual-frequency detection for different concentrations of BSA solutions are 0.081mg/ml and 0.088mg/ml, which have potential application in food chemical detection and biomedical treatment.