Horstmeyer Roarke, Chung Jaebum, Ou Xiaoze, Zheng Guoan, Yang Changhuei
Department of Electrical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
Bioimaging and Neurophotonics Lab, NeuroCure Cluster of Excellence, Charité Berlin, Humboldt University, Berlin 10117, Germany.
Optica. 2016 Aug;3(8):827-835. doi: 10.1364/OPTICA.3.000827. Epub 2016 Jul 27.
This paper presents a technique to image the complex index of refraction of a sample across three dimensions. The only required hardware is a standard microscope and an array of LEDs. The method, termed Fourier ptychographic tomography (FPT), first captures a sequence of intensity-only images of a sample under angularly varying illumination. Then, using principles from ptychography and diffraction tomography, it computationally solves for the sample structure in three dimensions. The experimental microscope demonstrates a lateral spatial resolution of 0.39 μm and an axial resolution of 3.7 μm at the Nyquist-Shannon sampling limit (0.54 and 5.0 μm at the Sparrow limit, respectively) across a total imaging depth of 110 μm. Unlike competing methods, this technique quantitatively measures the volumetric refractive index of primarily transparent and contiguous sample features without the need for interferometry or any moving parts. Wide field-of-view reconstructions of thick biological specimens suggest potential applications in pathology and developmental biology.
本文介绍了一种在三维空间对样品复折射率进行成像的技术。唯一所需的硬件是一台标准显微镜和一组发光二极管。该方法称为傅里叶叠层断层成像（FPT），首先在角度变化的照明条件下捕获样品的一系列仅强度图像。然后，利用叠层成像和衍射断层成像的原理，通过计算求解样品的三维结构。实验显微镜在110μm的总成像深度上，在奈奎斯特 - 香农采样极限下横向空间分辨率为0.39μm，轴向分辨率为3.7μm（在斯帕罗极限下分别为0.54μm和5.0μm）。与其他竞争方法不同，该技术无需干涉测量或任何移动部件，即可对主要为透明且连续的样品特征的体积折射率进行定量测量。厚生物标本的宽视场重建表明其在病理学和发育生物学方面具有潜在应用。
