光子自旋-轨道相互作用是在非同质媒介中光子的自旋角动量与光束传播及空间分布的轨道角动量间的相互作用，是当前纳米光学的前沿研究领域。超构表面是通过人工结构设计而具有超常物理特性的二维电磁表面，可以增强或操控光子自旋-轨道作用。本项目在课题组的前期研究基础上，研究利用超构表面操纵光子自旋-轨道作用的机理，并采用扫描近场光学显微系统和方法直接在介观尺度上对其进行表征测量。主要研究内容和拟解决的关键科学问题包括：研究超构表面与矢量光场的相互作用机理，设计可显著增强光子自旋-轨道作用的超构表面；将纳米天线与近场扫描探针结合，研发新型功能探针以及近场探测降噪技术，实现对光学近场的振幅、相位、旋性、偏振、磁场等多参数测量，从而对光子自旋-轨道作用进行测量表征；基于近场光学的互易定理，深入研究其衍生形式及近似形式，探索扫描探针的近场测量机理以实现对表征结果进行定量分析和解释。

Photonic spin-orbit interaction describes the interaction between spin angular momentum and orbital angular momentum carried by light in inhomogeneous medium, which is a frontier research field in nanophotonics. Metasurfaces are two-dimensional artificial electromagnetic surfaces with extraordinary physical properties produced by special structural designs, which can be used to enhance or manipulate the spin-orbit interaction of light in mesoscopic scale. Based on the research progress of our previous work, this project aims to study photonic spin-orbit interaction generated by metasurfaces and directly characterize the interaction in optical near field by using scanning near-field optical microscopy. The main research topics and the key scientific issues in this project are as follows. By studying the interaction mechanism between metasurfaces and vectorial optical field, we design metasurfaces that can notably enhance or manipulate photonic spin-orbit interaction. By incorporating nano-antenna into near-field scanning probe, we aim to develop several novel functional nano-probes with new noise-suppression technology, which are essential for the multi-parameter measurement in near field, including the amplitude, phase, helicity, polarization, and optical magnetism of the near field. These will form solid basis for the accurate characterization of the spin-orbit interaction in near field. Furthermore, by applying and studying the derivatives of reciprocity theorem in near field, we will further explore the mechanism of near-field measurement based on scanning probes, so as to better analyze and explain the characterization results quantitatively.