Spectroscopy and Spectral Analysis, Volume. 45, Issue 8, 2101(2025)
Research Progress on the Application of Metasurfaces in Terahertz Super-Resolution Imaging
Terahertz (THz) radiation, characterized by high penetrability, low energy, and unique fingerprint spectra, has extensive applications in nondestructive testing, biomedical imaging, security screening, and communications. However, traditional THz imaging systems are constrained by the long wavelength of THz waves and the scarcity of natural materials with high transmittance in this spectral range, resulting in limitations in resolution and sensitivity. These shortcomings hinder their ability to meet the technological demands of high-precision and trace-level detection. Metasurfaces, composed of subwavelength-scale structural units, enable precise control of THz wave propagation by modulating electromagnetic waves' phase, amplitude, and polarization. This capability allows them to overcome the diffraction limit of conventional optical systems, offering a viable solution for THz super-resolution imaging. This paper reviews the latest advancements in THz super-resolution imaging using metasurfaces, focusing on various structural types' design principles and application performance. Resonant structures enhance local fields at specific frequencies, enabling high-contrast imaging. Gradient-phase structures guide THz waves with precision through phase gradients. Multilayer metasurfaces leverage stacked-layer designs to achieve complex phase and amplitude modulation. Subwavelength gratings offer superior wavefront control, improving super-resolution imaging. Meanwhile, metamaterial reflective arrays achieve high-resolution wavefront modulation without needing lenses. Key design considerations for high-efficiency THz metasurfaces include structural design strategies, material selection, and precise phase and amplitude modulation techniques. The potential of optimized designs and novel materials in enhancing THz imaging performance and expanding its applications is also analyzed. Future research directions are proposed to address existing challenges in THz metasurface technology, such as complex fabrication processes, limited system compatibility, and material response constraints. These include: (1) developing novel low-loss materials to improve transmission efficiency and phase control; (2) integrating artificial intelligence to optimize metasurface design and performance; and (3) advancing system integration and miniaturization to facilitate the development of portable THz imaging devices for applications in high-precision imaging, medical diagnostics, and security screening. With continuous progress in new materials, intelligent design methodologies, and miniaturization technologies, THz metasurfaces are expected to achieve broader applications. Their advancement will drive the widespread adoption of high-precision imaging and portable devices, fostering new opportunities for scientific discovery and industrial innovation.
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LI Guang-ming, GE Hong-yi, JIANG Yu-ying, ZHANG Yuan, SUN Qing-cheng, ZHENG Hui-fang, LI Xing. Research Progress on the Application of Metasurfaces in Terahertz Super-Resolution Imaging[J]. Spectroscopy and Spectral Analysis, 2025, 45(8): 2101
Received: Nov. 19, 2024
Accepted: Sep. 5, 2025
Published Online: Sep. 5, 2025
The Author Email: JIANG Yu-ying (jiangyuying11@163.com)