Terahertz metasurface sensor by utilizing electromagnetically induced transparency

We present a water-shaped terahertz metasurface sensor based on the electromagnetically induced transparency (EIT) effect. The EIT resonance is generated by electromagnetic coupling between a double split ring and a rod-shaped structure to enhance sensitivity. The multipole decomposition is used to explain that the EIT resonance is dominated by electric dipoles (bright–dark mode coupling at 2.482 THz). Simulation results show that its sensitivity ( S ) to refractive index changes reaches 590 GHz/RIU. The experimental test shows that the limit of sensing detection for tartaric acid is 1 mg/ml, demonstrating its potential for application in drug residue monitoring and food safety testing.