Flexible terahertz Metamaterial sensor for sensitive detection of imidacloprid

In this paper, a flexible terahertz (THz) Metamaterial (MM) with high sensitivity is proposed for the detection of the pesticide imidacloprid. The MM sensor is composed of a polyimide (PI) substrate and a periodic aluminum (Al) split ring resonator array. The sensing performance of the MM is verified by both simulation and experiment. The simulation results show that the refractive index (RI) sensitivity of the proposed MM sensor is 220.7 GHz/RIU, and the figure of merit (FOM) of this MM is 1.52. Then, the sensing performance of the MM sensor is verified by using imidacloprid solutions with different concentrations. The experimental results show that the detection sensitivity of the MM sensor is 12.3 GHz/(mg/ml), and the limit of detection (LOD) is 0.0112 mg/ml. The THz MM sensor proposed in this paper is flexible, simple to make, cost-effective, highly sensitive and has a very broad application prospect in the concentration detection of pesticides such as imidacloprid.