Meta-terahertz sensing: Metamaterial-enhanced rapid and efficient detection of food contaminants

Terahertz (THz) technology, capable of capturing molecular vibrational and rotational information, offers a promising approach for food contaminant detection. However, the inherently weak interaction between THz waves and low-concentration contaminants limits detection sensitivity. To address above issue, metamaterial THz (Meta-THz) sensors have been developed to amplify THz signals and improve sensitivity. Therefore, this review introduces the core elements of THz systems, followed by a detailed exposition of the fabrication process, sensor principles, and detection mechanisms of Meta-THz. Then, the review systematically summarizes recent advances in Meta-THz technology for detecting food contaminants including pesticides, antibiotics and toxins. Importantly, key methods and innovations are discussed, including the design of resonant layer structures, selection of dielectric materials, and data analysis strategies incorporating deep learning and physics-informed models. We highlight intrinsic approaches such as optimizing resonant layer conductivity, structure complexity, and dielectric properties and extrinsic approaches, including surface functionalization with recognition elements and external modulation, to achieve specific and selective contaminant identification. The review also examines major challenges in the field, including miniaturization, production optimization, tunable sensor performance, and advanced data analysis, and proposes potential solutions through hybrid materials, heterogeneous integration, intelligent sensing platforms and advanced computational strategies. Overall, this work provides a comprehensive and practical perspective on Meta-THz, offering guidance for future development of high-sensitivity, specific, and robust food contaminant detection systems.