Accurate sizing of individual nanoparticles is crucial for the understanding of their physical and chemical properties and for their use in nanoscale devices. Optical sizing methods are non-invasive, rapid, and versatile. However, the low optical response of weakly absorbing subwavelength dielectric nanoparticles poses a fundamental challenge for their optical metrology. We demonstrate scalable optical sizing of such nanoparticles based on confocal scanning microscopy. The method is absolutely calibrated by correlating the optical signatures in the scattered pump laser signal to the ground truth nanoparticle sizes measured by an atomic force microscope. Using an air objective with a numerical aperture of 0.9, we measured the sizes of nanodiamond particles ranging from 35 to 175 nm, with an average error of ± 12.7 nm compared to the ground truth sizes. This technique paves the way for the metrology of a wide range of weakly scattering nano-objects for applications in biomedicine, catalysis, nanotechnology, and quantum optics.

中文翻译：

---

通过共聚焦扫描光学显微镜快速确定深亚波长介电纳米粒子的绝对尺寸

单个纳米颗粒的准确尺寸对于理解它们的物理和化学特性以及它们在纳米器件中的使用至关重要。光学尺寸测量方法是非侵入性的、快速的和通用的。然而，弱吸收亚波长介电纳米粒子的低光学响应对其光学计量提出了根本挑战。我们展示了基于共聚焦扫描显微镜的此类纳米粒子的可扩展光学尺寸。该方法通过将散射泵浦激光信号中的光学特征与原子力显微镜测量的真实纳米颗粒尺寸相关联来进行绝对校准。使用数值孔径为 0.9 的空气物镜，我们测量了纳米金刚石颗粒的尺寸范围为 35 到 175 nm，平均误差为 ± 12。7 nm 与地面实况尺寸相比。该技术为广泛的弱散射纳米物体的计量学铺平了道路，可应用于生物医学、催化、纳米技术和量子光学。