Since the seminal work by J. H. Poynting, light has been known to carry momentum and angular momentum. The typical dynamical features of light and its interactions—termed spin–orbit interactions (SOIs), which have been investigated intensely over the last 30 years—play a crucial role in various light-matter interactions, for example: spin Hall effect, spin–orbit conversion, helicity-controlled unidirectional excitation of light, and their inverse effects, which leads to plenty of applications including optical manipulation, communications, imaging, sensing, nanometrology, on-chip optoelectronic technologies and interdisciplinary researches. In particular, the SOI of light in isotropic inhomogeneous media is a fine, subwavelength effect accomplished through the intrinsic coupling between light's phase, polarization and position. Therefore, the traditional methods of near-field measurements, such as near field scanning optical microscopy (NSOM), have been widely employed to reveal the optical SOIs intuitively by measuring the intensity of light. Very recently, with modern advanced nanofabrication techniques, many measurement techniques based on nanoparticles, nanoantennas, and nanoprobes of special designs have been proposed to understand the optical SOIs visually by characterizing the polarization and spin/orbital features of light. This endeavor has led to the development of chiral quantum optics, spin optics, and topological photonics, and resulted in novel applications requiring optical manipulations and angular momentum communications, chiral imaging, nanometrology, and robust spin-based devices and techniques for quantum technologies. Here, we review the near-field techniques for measurements of optical SOIs together with their potential applications. We start with a theoretical overview of momentum and angular momentum properties of generic optical fields and typical phenomena involving optical SOIs. Then, we overview the theoretical basis and latest achievements of the near-field measurement techniques, including NSOM, optical manipulations, nanoantenna, and nanoprobes of special designs, all relevant to optical SOIs. A comprehensive classification is then constructed of all known methods of optical near-field measurements for the SOI of light and novel techniques identified for future applications.

自从 JH Poynting 的开创性工作以来，人们就知道光具有动量和角动量。光及其相互作用的典型动力学特征——称为自旋轨道相互作用 (SOI)，在过去 30 年中得到了深入研究——在各种光物质相互作用中发挥着至关重要的作用，例如：自旋霍尔效应、自旋——轨道转换、螺旋控制的光单向激发及其逆效应，导致了大量应用，包括光学操纵、通信、成像、传感、纳米计量、片上光电技术和跨学科研究。特别是，各向同性非均匀介质中光的 SOI 是一种精细的亚波长效应，通过光的相位、偏振和位置之间的固有耦合实现。所以，近场测量的传统方法，如近场扫描光学显微镜（NSOM），已被广泛用于通过测量光强度直观地揭示光学 SOI。最近，借助现代先进的纳米制造技术，已经提出了许多基于纳米粒子、纳米天线和特殊设计的纳米探针的测量技术，通过表征光的偏振和自旋/轨道特征来直观地理解光学 SOI。这一努力导致了手性量子光学、自旋光学和拓扑光子学的发展，并产生了需要光学操纵和角动量通信、手性成像、纳米计量学以及稳健的基于自旋的器件和量子技术技术的新应用。这里，我们回顾了用于测量光学 SOI 的近场技术及其潜在应用。我们首先对通用光场的动量和角动量特性以及涉及光学 SOI 的典型现象进行理论概述。然后，我们概述了近场测量技术的理论基础和最新成果，包括与光学 SOI 相关的 NSOM、光学操纵、纳米天线和特殊设计的纳米探针。然后，根据光的 SOI 的所有已知光学近场测量方法和为未来应用确定的新技术，构建了一个综合分类。我们首先对通用光场的动量和角动量特性以及涉及光学 SOI 的典型现象进行理论概述。然后，我们概述了近场测量技术的理论基础和最新成果，包括与光学 SOI 相关的 NSOM、光学操纵、纳米天线和特殊设计的纳米探针。然后，根据光的 SOI 的所有已知光学近场测量方法和为未来应用确定的新技术，构建了一个综合分类。我们首先对通用光场的动量和角动量特性以及涉及光学 SOI 的典型现象进行理论概述。然后，我们概述了近场测量技术的理论基础和最新成果，包括与光学 SOI 相关的 NSOM、光学操纵、纳米天线和特殊设计的纳米探针。然后，对所有已知的光 SOI 光学近场测量方法和为未来应用确定的新技术进行综合分类。