Zhou Yangyang, Li Jue, Xiao Wen, Chen Huanyang
Opt Lett. 2022 Aug 1;47(15):3820-3823. doi: 10.1364/OL.466126.
Super-focusing light using metamaterials and metasurfaces is of paramount importance in several applications, from integrated optics to microwave engineering and sensing. However, there are still some difficulties to realize broadband achromatic aberration highly efficient super-focusing from the far field to far field or quasi far field. In this Letter, based on conformal transformation optics, we propose a generalized conformal Luneburg lens (GCLL), which provides a new, to the best of our knowledge, strategy for quasi-far-field super-focusing with broadband (0.9-1.3 THz) achromatic aberration and high efficiency (above 60%). A relatively high numerical aperture (NA of 0.63) and sub-diffraction-limited resolution (FWHM of 0.45λ) are also obtained. The sample of the GCLL was designed using gradient metamaterials. The numerical simulation results verify that the focusing effects of the designed samples are consistent with the performance of the ideal GCLL.
使用超材料和超表面的超聚焦光在从集成光学到微波工程与传感等多种应用中至关重要。然而，要实现从远场到远场或准远场的宽带消色差高效超聚焦仍存在一些困难。在本信函中，基于共形变换光学，我们提出了一种广义共形伦伯格透镜（GCLL），据我们所知，它为具有宽带（0.9 - 1.3太赫兹）消色差和高效率（高于60%）的准远场超聚焦提供了一种新策略。还获得了相对较高的数值孔径（0.63）和亚衍射极限分辨率（0.45λ的半高宽）。GCLL样本是使用梯度超材料设计的。数值模拟结果验证了所设计样本的聚焦效果与理想GCLL的性能一致。
