Abstract
Inspired by the development of terahertz (THz) technology, the demand for THz sensors with high quality and high sensitivity is significantly increasing. In this study, one-dimensional metallic metamaterials based on cavity mode resonance are proposed for sensing applications in the THz regime. Owing to the strong energy concentration in the cavity, metamaterials with a high quality factor were obtained. Thus, the presented device not only achieved narrowband selective absorption but also exhibited excellent refractive index sensing with high sensitivity, figure of merit, and quality factor. The physical mechanism was verified by comparing the simulation results with that of the coupled mode theory. The polarization dependence of absorption and dual-band sensing, which can be actively tuned by the broken symmetry between two adjacent units, were also discussed. Consequently, this study may open up new avenues for the development of biosensing and imaging applications.
Highlights
Terahertz (THz) sensing technology is a powerful tool for medical imaging, agricultural detection, radio astronomy, and wireless communications.1–6 For decades, THz sensing has become an important research topic because of its advantages of being labelfree and noninvasive.7–13 In general, the core method involves the strengthening of light–matter interactions between the THz wave and analytes, inspiring significant studies elucidating several physical mechanisms
The presented device achieved narrowband selective absorption and exhibited excellent refractive index sensing with high sensitivity, figure of merit, and quality factor
The sensor based on cavity mode resonance (CMR) is studied with the incident light in TE polarization
Summary
Terahertz (THz) sensing technology is a powerful tool for medical imaging, agricultural detection, radio astronomy, and wireless communications. For decades, THz sensing has become an important research topic because of its advantages of being labelfree and noninvasive. In general, the core method involves the strengthening of light–matter interactions between the THz wave and analytes, inspiring significant studies elucidating several physical mechanisms. When the incident light frequency matches the resonance frequency of the cavity mode, a narrow band of selective absorption was observed. Such a device based on CMR significantly improves the performance of THz sensors; their sharp resonances have a narrow linewidth and an ultrahigh Q factor, figure of merit (FOM), and sensitivity. Polarization dependence of incident light and double-band absorption due to broken symmetry were evaluated in this study. These findings provide a new guideline for the design of THz sensors in the future
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