Multifunctional, active and nonlinear optical smart metasurfaces

在当前的光学和纳米光子学研究中，能够执行多个并行任务并以紧凑的占地面积主动控制线性和非线性光学响应的智能平面系统是非常有需求的。拟议的项目将以光学变形表面领域的最新发展为基础。这种亚表面是由人造超薄亚波长积木组装而成的，能够实现全面和前所未有的电磁响应。最近，已经表明，元表面可以容易地用于改变光的光束传输、作为光束整形元件以及用于编码信息。然而，亚表面仍然面临着一些挑战，特别是对于复杂的各向异性结构和层叠的层，需要额外的努力来考虑大量的电磁耦合响应和各种共振现象。只有了解这些效应及其对光学性质的影响，才能提供清晰的物理图像，并允许直接有效的设计。本项目旨在对具有多功能、主动性、线性和非线性特性的智能亚表面进行理论和实验研究，这些特性可以超越传统的光学元件。为了获得具有定制设计的多任务和主动光学特性的亚表面，必须建立理论模型，并且必须实现功能或活性材料的合理工程集成。为了增加光学亚表面的功能，我们将针对多光束参数的同时调制和并行多路复用算法的自适应问题。我们的目标是开发由准原子制成的亚表面，它可以同时改变通过光的不止一种属性，例如偏振、相位和幅度。此外，为了获得超表面属性的动态调制，我们将在超原子的设计中使用活性材料，这些超原子可以通过外部刺激改变其属性。该项目已被组织为四个主要推动力，分别侧重于基本机制、深度学习以实现更快的设计、多功能以及对线性和非线性效应的主动控制，这将为未来的应用提供重大收益。所有四个推进都是为了协同和交叉。该项目开发的技术和算法将被整合到一个共享系统/设备中，以提高整体性能并实现智能光学元件。这一合作项目结合了帕德伯恩大学和北京理工大学两个团队在纳米光子学、衍射光学、全息术和非线性光学研究方面的专业知识，开展了超紧凑智能亚表面的创新研究。

Smart planar systems that can perform a number of concurrent tasks and actively control the linear and nonlinear optical response with compact footprint are highly on-demand in current optics and nanophotonics research. The proposed project will build on recent developments in the field of optical metasurfaces. Such metasurfaces are assembled artificial ultrathin sub-wavelength building blocks capable of achieving comprehensive and unprecedented electromagnetic response. Recently, it has been shown that metasurfaces can readily be used for altering the beam propagation of light, as beam shaping elements, and for encoding information. However, there are still several challenges facing metasurfaces, especially for complex anisotropic structures and cascaded layers, which require extra efforts by considering numerous electro-magnetic coupling responses and various resonance phenomena. Only by understanding these effects and their influence on the optical properties can provide a clear physical picture and would allow for a straightforward efficient design. This project aims at theoretical and experimental studies of smart metasurfaces with multifunctional, active, linear and nonlinear properties that can surpass traditional optical elements. In order to attain metasurfaces with custom-designed multi-tasks and active optical characteristics, theoretical models have to be developed and judiciously engineered integrations of functional or active materials must be realized. For increasing the functionality of optical metasurfaces, we will target the problem of simultaneous modulation of multiple beam parameters and the adaption of parallel multiplexing algorithms. Our goal is the development of metasurfaces made of meta-atoms that can alter more than one property of the passing light, e.g. polarization, phase, and amplitude simultaneously, at the time. In addition, to gain access to the dynamical modulation of properties of metasurfaces we will utilize active materials in the design of the meta-atoms that can alter their properties by an external stimulus. The project has been organized into four main thrusts that focus on fundamental mechanisms, deep learning for faster design, multi-functionality and active control of linear and nonlinear effects, which can provide significant gains for future applications. All four thrusts are outlaid to be synergistic and cross-cutting. The techniques and algorithms developed within this project will be combined into a single shared system/device to enhance overall performance and enable smart optical elements. This collaborative project combines the expertise from two groups at Paderborn University and Beijing Institute of Technology in nanophotonics, diffractive optics, holography, and nonlinear optics research, to carry out innovative research for ultra-compact smart metasurfaces.