Near-field coupled nonlocal optical metasurface for versatile polarization and bandstructure manipulations

用于多种偏振和能带结构操纵的近场耦合非局域光学超表面

• 批准号: 514785315
• 负责人: Professor Dr. Thomas Zentgraf
• 金额: --
• 依托单位: Ultrafast Nanophotonics Group
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/514785315?language=en
• 关键词: Near; field; coupled; nonlocal; optical

Recent advances in the modern nanotechnology gave birth to ‘thin-flat-optics’ elements (the so-called optical metasurfaces), based on nanoscale structures, capable of versatile tailoring on the responses to light such as wave-fronts, amplitudes, polarization, and frequency. Despite the extremely reduced dimensions of the ‘flat-optics’ elements, the working principle mostly remains being the Huygens-Fresnel principle, virtually the same to traditional optical elements. However, there exists a major difference between the ‘flat-optics’ elements compared to the traditional ones. The traditional optical lenses manipulate wavefronts through the length of optical path inside the bulk material, while ‘flat-optics’ devices rely on resonances effects wherein drastic amplitude and phase changes can be manifested in the spectral responses. These spectral responses are exerted by the subwavelength optical resonances residing on the optical nano-resonators.An analog of the subwavelength optical resonances are the electron orbits sitting on lattice of atoms in solids. Akin to the electron’s orbits, the optical resonances could ‘talk’ to each other through near-field couplings and build up a collective response unprecedented in traditional optical elements, for instance chiral metasurfaces that are only responsive to one handedness of circular polarizations. In this proposal, we are going to scrutinize the theoretical framework and design logic for taming the crosstalk between optical nano-resonators and further develop their prospect for wave manipulations in both linear and nonlinear applications. A tailored inter-unit coupling with a strong nonlocal response could effectively modify both the scattering properties and the wave propagation inside the metasurface. Owning to the extreme subwavelength feature size in nano-scale photonic resonators, new types of spin-orbital coupled metasurfaces with strongly enhanced circular dichroism, as well as strongly enhanced linear and nonlinear light-matter interactions with photonic topological flat bands are envisioned and will be studied here.

现代纳米技术的最新进展催生了基于纳米级结构的“薄平面光学”元件（所谓的光学超颖表面），能够对光的响应进行多功能定制，例如波前，振幅，偏振和频率。尽管“平面光学”元件的尺寸大大减小，但其工作原理基本上仍然是惠更斯-菲涅耳原理，与传统光学元件几乎相同。然而，与传统元件相比，“平面光学”元件之间存在着重大差异。传统的光学透镜通过体材料内部的光路长度来操纵波前，而“平面光学”设备依赖于共振效应，其中剧烈的振幅和相位变化可以在光谱响应中表现出来。这些光谱响应是由位于纳米光学谐振器上的亚波长光学谐振产生的，亚波长光学谐振的模拟是位于固体中原子晶格上的电子轨道。类似于电子的轨道，光学共振可以通过近场耦合彼此“交谈”，并建立传统光学元件中前所未有的集体响应，例如仅对圆偏振的单手性做出响应的手性超颖表面。在本论文中，我们将详细探讨抑制光学奈米共振器间串音的理论架构与设计逻辑，并进一步发展其在线性与非线性应用中的波操控前景。具有强非局部响应的定制单元间耦合可以有效地修改超颖表面内的散射特性和波传播。由于极端的亚波长特征尺寸在纳米尺度的光子谐振器，具有强烈增强的圆二色性，以及强烈增强的线性和非线性光-物质相互作用的光子拓扑平坦带的新型自旋轨道耦合超颖表面的设想，并将在这里进行研究。