Chen Jin, Huang Shao-Xin, Chan Ka Fai, Wu Geng-Bo, Chan Chi Hou
State Key Laboratory of Terahertz and Millimeter Waves, City University of Hong Kong, Hong Kong, 999077, China.
Department of Electrical Engineering, City University of Hong Kong, Hong Kong, 999077, China.
Nat Commun. 2025 Jan 3;16(1):363. doi: 10.1038/s41467-024-55624-w.
Terahertz (THz) lens constitutes a vital component in the THz system. Metasurfaces-based THz metalenses and classical bulky lenses are severely constrained by chromatic/ spherical aberration and the diffraction limit. Consequently, achromatic super-resolution THz lenses are urgently needed. In this study, through translating the required phase distribution into a refractive index (RI) profile with a specific thickness, an innovative approach to designing THz metalenses is proposed and achieved by dielectric gradient metamaterials. The samples fabricated by 3D printing can realize achromatic super focusing with a numerical aperture (NA) of 0.555 from 0.2 to 0.9 THz. Submillimeter features separated by approximately 0.2 mm can be resolved with high precision, such as glass fabric patterns within FR4 panels and fibrous tissue on leaves, with a field of view (FOV) of 90°. Our approach offers a feasible and cost-effective means to implement THz super-resolution imaging, which holds great potential in non-destructive testing and biomedical imaging.
太赫兹（THz）透镜是太赫兹系统中的关键部件。基于超表面的太赫兹金属透镜和传统的笨重透镜受到色差/球差和衍射极限的严重限制。因此，迫切需要消色差超分辨率太赫兹透镜。在本研究中，通过将所需的相位分布转换为具有特定厚度的折射率（RI）分布，提出了一种设计太赫兹金属透镜的创新方法，并通过介电梯度超材料得以实现。通过3D打印制造的样品能够在0.2至0.9太赫兹范围内实现数值孔径（NA）为0.555的消色差超聚焦。能够高精度分辨间隔约0.2毫米的亚毫米特征，如FR4面板内的玻璃纤维图案和叶片上的纤维组织，视场（FOV）为90°。我们的方法为实现太赫兹超分辨率成像提供了一种可行且经济高效的手段，在无损检测和生物医学成像方面具有巨大潜力。
