High sensitivity terahertz metamaterial sensor for trace pesticide detection†

Abstract

Pesticides play a vital role in agriculture by protecting crops from pests and diseases and ensuring high yields. However, improper use poses severe risks to human health and the environment, emphasizing the need for the precise detection of pesticide residues. Methods like chromatography and biosensors are commonly used, but each has limitations in stability, selectivity, or applicability. THz metamaterial (MM) sensors offer high sensitivity through changes in spectral response, making them a promising alternative to address many of these challenges. They enable the identification of specific pesticide molecules at extremely low concentrations through resonance frequency shifts. By incorporating innovative design features, these sensors can detect trace pesticide residues with ease, affordability, and rapid response. In this work, we designed an MM sensor with near-perfect absorption at its resonance frequency. The high absorption of 99.43% resulted from impedance matching with the free space. The MM demonstrated an impressive figure of merit, highlighting its effectiveness as a sensing device. This approach has significant potential for food safety and environmental monitoring applications, providing efficient and reliable detection solutions.