Metallic mesh devices-based terahertz parallel-plate resonators: characteristics and applications

The capability to design, fabricate, and optimize metamaterials based on various structures and material platforms has been crucial for the rapid development of modern terahertz (THz) technology. While the detailed structures of artificial unit cells within a metamaterial is certainly worth investigating, there has been increasing demand to integrate novel metamaterials with a traditional functional photonic device to form a hybrid device, whose performance is so significantly improved as to be promising for real-world applications. In this study, we proposed, for the first time, a THz parallel-plate resonator based on metallic mesh devices (MMDs) for chemical sensing applications. We studied the influences of various structural parameters through simulations, fabricated MMD-based resonator devices, and fully characterized the device performance through THz spectroscopy experiments. Furthermore, we experimentally demonstrated that our device can detect a doxycycline hydrochloride aqueous solution whose concentrations is as low as 1 mg L−1 through resonance frequency shifts, evidencing the device sensitivity capable of delicate chemical sensing tasks. Our work presents a practical and low cost architecture for chemical sensing using THz radiation, which opens new avenues for numerous useful THz devices based on metamaterials.