作者单位
摘要
1 江南大学理学院光电科学与工程系, 江苏 无锡 214122
2 中国科学院长春光学精密机械与物理研究所, 吉林 长春 130033
超构表面可看成二维超构材料, 能够在表面空间内控制光场分布。可调谐超构表面作为新的设计需求成为目前热门研究领域。利用动态可调谐的超构表面对光场的相位、偏振、强度等维度精准调控, 以及调控光场与物质的相互作用研究是当前基础科学与多学科融合发展的前沿研究。系统介绍了动态可调谐超构表面在结构色、偏振转换、完美吸收、图像处理等光场多维度调控及应用方面取得的最新研究进展, 总结了可调谐超构表面的研究前沿与应用前景。
可调谐超构表面 微纳光子器件 人工微纳结构 光场调控 器件设计 active metasurface micro-nano photonic device artificial nano-structure spectral control device design 
光学与光电技术
2022, 20(4): 36
Author Affiliations
Abstract
1 Pohang University of Science and Technology, Department of Mechanical Engineering, Pohang, Republic of Korea
2 Pohang University of Science and Technology, Department of Chemical Engineering, Pohang, Republic of Korea
3 POSCO–POSTECH–RIST Center for Flat Optics and Metaphotonics, Pohang, Republic of Korea
Metasurfaces have attracted great attention due to their ability to manipulate the phase, amplitude, and polarization of light in a compact form. Tunable metasurfaces have been investigated recently through the integration with mechanically moving components and electrically tunable elements. Two interesting applications, in particular, are to vary the focal point of metalenses and to switch between holographic images. We present the recent progress on tunable metasurfaces focused on metalenses and metaholograms, including the basic working principles, advantages, and disadvantages of each working mechanism. We classify the tunable stimuli based on the light source and electrical bias, as well as others such as thermal and mechanical modulation. We conclude by summarizing the recent progress of metalenses and metaholograms, and providing our perspectives for the further development of tunable metasurfaces.
tunable metasurface active metasurface reconfigurable metasurface multifunctional metahologram varifocal metalens 
Advanced Photonics
2022, 4(2): 024001
Author Affiliations
Abstract
1 Fudan University, Department of Physics and State Key Laboratory of Surface Physics, Shanghai, China
2 Shanghai Research Center for Quantum Sciences, Shanghai, China
The ability to generate and manipulate broadband chiral terahertz waves is essential for applications in material imaging, terahertz sensing, and diagnosis. It can also open up new possibilities for nonlinear terahertz spectroscopy and coherent control of chiral molecules and magnetic materials. The existing methods, however, often suffer from low efficiency, narrow bandwidth, or poor flexibility. Here, we propose a novel type of laser-driven terahertz emitters, consisting of metasurface-patterned magnetic multilayer heterostructures, that can overcome the shortcomings of the conventional approaches. Such hybrid terahertz emitters combine the advantages of spintronic emitters for being ultrabroadband, efficient, and highly flexible, as well as those of metasurfaces for the powerful control capabilities over the polarization state of emitted terahertz waves on an ultracompact platform. Taking a stripe-patterned metasurface as an example, we demonstrate the efficient generation and manipulation of broadband chiral terahertz waves. The ellipticity can reach >0.75 over a broad terahertz bandwidth (1 to 5 THz), representing a high-quality and efficient source for few-cycle circularly polarized terahertz pulses with stable carrier waveforms. Flexible control of ellipticity and helicity is also demonstrated with our systematic experiments and numerical simulations. We show that the terahertz polarization state is dictated by the interplay between laser-induced spintronic-origin currents and the screening charges/currents in the metasurfaces, which exhibits tailored anisotropic properties due to the predesigned geometric confinement effects. Our work opens a new pathway to metasurface-tailored spintronic emitters for efficient vector-control of electromagnetic waves in the terahertz regime.
chiral terahertz generation active metasurface time-domain terahertz spectroscopy 
Advanced Photonics
2021, 3(5): 056002
作者单位
摘要
西南交通大学 电磁场与微波技术研究所,成都 610031
提出了一种使用散射方向图的动态可重构以实现雷达散射截面增强的捷变设计方法。结合变容二极管加载,使用具有嵌入式偏置回路的物理单元,所提出的有源超表面可以在具有梯度电压的外加直流偏置下,对平面电磁波的正入射或斜入射产生可电调的反射系数相位分布,以达到对反射波角度的灵活重定向,进而有助于单站或双站雷达散射截面增强的捷变效果。以导电平板为例,对三种不同的入射反射场景进行了计算与全波仿真,在设计频率10 GHz处,所提出的设计产生了可重构的散射方向图,表明了该设计对反射波角度的实时控制,并结合实验测量验证了单站与双站雷达散射截面的有效增强结果。
后向散射 双站散射 有源超表面 方向图重构 monostatic scattering bistatic scattering active metasurface reconfigurable pattern 
强激光与粒子束
2021, 33(4): 043002

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