Wan Chengwei, Dai Chenjie, Zhang Jian, Wan Shuai, Li Zile, Zheng Guoxing, Zhang Xuefeng, Li Zhongyang
Electronic Information School, Wuhan University, Wuhan, 430072, China.
Institute of Advanced Magnetic Materials, College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, 310018, China.
Small. 2021 Aug;17(34):e2100561. doi: 10.1002/smll.202100561. Epub 2021 Jul 20.
As two independent optical sub-fields, diffraction optics and plasmonics both have been used for wavefront shaping and beam steering. However, the two separate concepts have always been developing as two parallel directions, which have not met for studying their structural hybridization to discover new potentials. For instance of the flat metasurfaces, even though the geometric parameters including shape, size, and periodicity have been studied, it remains mostly unexplored for the 3D spatial height variation. Here, a new type of all-metallic 3D meta-prism is proposed and experimentally demonstrated by hybridizing the localized surface plasmonic resonances (LSPR) and the blazed grating diffraction, which enables strong polarization-dependent behaviors to steer broadband visible light to drastically inverse directions. The nanofabrication of 3D meta-prism is achieved by nanostencil lithography with electron-beam evaporation. Such meta-prism could also enable to split different visible light (green, blue, and red) with high-efficiency contrast (≈10). By the mirror-symmetry arrangement, a multifunctional surface is demonstrated with polarization-/wavelength-multiplexing wavefront-shaping functions (concave, convex, or flat mirror). This unique 3D meta-prism enjoys great simplicity and versatility in broadband beam steering through the incorporation of plasmonic and diffractive effects and can be utilized in various applications including dichroic-prism splitters, multifunctional meta-mirrors, etc.
作为两个独立的光学子领域，衍射光学和表面等离激元光学都已被用于波前整形和光束控制。然而，这两个独立的概念一直沿着两个平行的方向发展，尚未结合起来研究其结构杂交以发掘新的潜力。以平面超表面为例，尽管已经研究了包括形状、尺寸和周期性在内的几何参数，但对于三维空间高度变化仍大多未被探索。在此，通过将局域表面等离激元共振（LSPR）与闪耀光栅衍射相结合，提出并通过实验证明了一种新型的全金属三维元棱镜，它能够实现强烈的偏振依赖行为，将宽带可见光引导至截然不同的相反方向。三维元棱镜的纳米制造是通过纳米模板光刻结合电子束蒸发实现的。这种元棱镜还能够以高效对比度（≈10）分离不同的可见光（绿色、蓝色和红色）。通过镜面对称排列，展示了一种具有偏振/波长复用波前整形功能（凹面、凸面或平面镜）的多功能表面。这种独特的三维元棱镜通过结合等离激元和衍射效应，在宽带光束控制方面具有极大的简单性和通用性，可用于包括二向色棱镜分光器、多功能元镜等各种应用中。
