超颖表面是一类通过特殊结构设计而具有超常物理特性的人造电磁表面，是当前纳米光学领域的一个前沿研究热点。本项目在课题组前期研究成果的基础上，对一类基于手性相互作用的光学超颖表面的近远场调控特性及其功能应用开展深入系统的研究。主要研究内容和拟解决的关键科学问题包括：研究超颖表面对光场相位和振幅的单独和同时调控方法，使之具备对光场复振幅的全面调控能力；研究超颖表面的复用机制，实现波长、偏振、空间等复用，及不同轨道角动量的涡旋光束和其它矢量光束的复用；通过研究超颖表面发光器件、分形或多尺度手性超颖表面、超颖表面像素的实时调控方法等，深入理解超颖表面与矢量光场的相互作用机理，发展智能化、可主动调控的功能器件；从共振增强偏振转换效率、阻抗匹配设计、使用有源增益介质补偿损耗等方案入手，探索提高超颖表面能量利用率的有效方法；研究超颖表面的近场调控特性并发展新应用，如用于检测具有特定拓扑电荷数的涡旋光束等。

Metasurfaces are a class of artificial electromagnetic surfaces with extraordinary physical properties produced by special structural designs, which have formed a frontier research field in nanophotonics nowadays. Based on the research progress of our previous work, this project plans to perform an in-depth and systematic study on the near-field and far-field modulation properties and functional applications of a type of optical metasurfaces that are based on the chiral interaction between optical field and the nanostructured surfaces. The main research topics and the key scientific issues to be dealt with in this project are as follows. We study the principle and methods of modulating the phase and amplitude of optical field independently or simultaneously by using the metasurfaces, by which to realize the complete modulation of the complex amplitude of optical field. We study the multiplexing techniques of the metasurfaces, including the multiplexing of wavelength, polarization, space, and the vectorial optical beams such as vortex beams with different optical angular momentums. By studying light emission devices based on metasurfaces, fractal and multiscale chiral metasurfaces, and the real-time modulation of metasurface pixels, we aim to better understand the interaction between metasurfaces and the vectorial optical field, by which to develop more intelligent and active functional devices. By exploring some schemes such as the enhancement of polarization conversion by resonances, the design of impedance-matching structures, and the compensation of energy loss by using gain media, we aim to find out effective methods to improve the energy utilization efficiency in metasurfaces. Furthermore, we study the near-field properties of metasurfaces, by which to develop new functional applications such as the devices for characterizing vortex beams with specific topological charges.