There is an increasing demand for new technologies to rapidly measure individual nanoparticles in situ for applications, including early-stage diagnosis of human diseases and environmental monitoring. Here, we demonstrate a label-free wide-field optical microscopy capable of sizing dispersed non-luminescent dielectric nanoparticles (with diameters down to 22 nm) with 10 nm accuracy. This technique utilizes enhanced nanoparticle-perturbed scattering by surface plasmons created on a gold film. In the meantime, an azimuthal rotation illumination module is installed on this microscope and a differential image processing technique is carried out. The relationship between the scattering intensity and the particle size was experimentally measured with good consistency with the theoretical prediction. The capability of precise measurement of the size of dispersed nanoparticles within a larger field of view in a label-free, non-invasive and quantitative manner may find broad applications involving single nanoparticle chemistry and physics.

对原位快速测量单个纳米粒子的新技术的需求不断增加用于应用，包括人类疾病的早期诊断和环境监测。在这里，我们展示了一种无标记的宽视场光学显微镜，能够以 10 nm 的精度确定分散的非发光介电纳米粒子（直径低至 22 nm）的大小。该技术利用金膜上产生的表面等离子体激元增强纳米粒子扰动散射。同时，在该显微镜上安装了方位角旋转照明模块，并进行了差分图像处理技术。散射强度和粒径之间的关系是通过实验测量的，与理论预测具有良好的一致性。在无标记的更大视野内精确测量分散纳米颗粒尺寸的能力，