High-sensitivity detection of trace imidacloprid and tetracycline hydrochloride by multi-frequency resonance metamaterials

Highly sensitive detection of trace pesticide residues in food products is needed. The terahertz metamaterial (THz MM) is one of the most important detection approaches with high sensitivity by enhancing the interaction between light and matter. In this work, single and double U-shape resonator THz MMs were fabricated based on split-ring resonators with multi-frequency resonance achieved. The low and high-frequency resonant modes (LFRM & HFRM) coexisted in THz MMs and the experimental sensitivity of imidacloprid up to 0.1 ng could only be detected under HFRM. Then tetracycline hydrochloride was used to verify the above conclusions. Multi-frequency resonator THz MMs may be helpful for the high-sensitivity detection of trace pesticide residues in agricultural products. This study truly demonstrates important applications to improve analytical performance and achieve delicate biological detection.