Institute for Biomedical Materials and Devices (IBMD), Faculty of Science, University of Technology Sydney, Sydney, NSW, 2007, Australia.
School of Electrical and Data Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Ultimo, NSW, 2007, Australia.
Nat Commun. 2021 Apr 1;12(1):2019. doi: 10.1038/s41467-021-22283-0.
Sub-diffraction limited localization of fluorescent emitters is a key goal of microscopy imaging. Here, we report that single upconversion nanoparticles, containing multiple emission centres with random orientations, can generate a series of unique, bright and position-sensitive patterns in the spatial domain when placed on top of a mirror. Supported by our numerical simulation, we attribute this effect to the sum of each single emitter's interference with its own mirror image. As a result, this configuration generates a series of sophisticated far-field point spread functions (PSFs), e.g. in Gaussian, doughnut and archery target shapes, strongly dependent on the phase difference between the emitter and its image. In this way, the axial locations of nanoparticles are transferred into far-field patterns. We demonstrate a real-time distance sensing technology with a localization accuracy of 2.8 nm, according to the atomic force microscope (AFM) characterization values, smaller than 1/350 of the excitation wavelength.
亚衍射极限定位荧光发射器是显微镜成像的关键目标。在这里，我们报告说，当单个上转换纳米粒子（包含多个随机取向的发射中心）置于镜子顶部时，它们可以在空间域中产生一系列独特的、明亮的、位置敏感的图案。通过我们的数值模拟支持，我们将这种效应归因于每个单发射器与其镜像之间的干涉之和。结果，这种配置产生了一系列复杂的远场点扩散函数（PSF），例如高斯形、甜甜圈形和弓箭靶形，强烈依赖于发射器与其镜像之间的相位差。通过这种方式，纳米粒子的轴向位置被转换为远场图案。根据原子力显微镜（AFM）的特征值，我们展示了一种具有 2.8nm 定位精度的实时距离传感技术，小于激发波长的 1/350。
