Wolf phase tomography (WPT) of transparent structures using partially coherent illumination
Wolf phase tomography (WPT) of transparent structures using partially coherent illumination
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DOI：
10.1038/s41377-020-00379-4
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发表时间：
2020-08-19
影响因子：
19.4
通讯作者：
Popescu, Gabriel
中科院分区：
文献类型：
--
作者：
Chen, Xi;Kandel, Mikhail E.;Popescu, Gabriel
1969年，埃米尔·沃尔夫（Emil Wolf）提出了使用相干全息成像的衍射层析成像技术，从透明、不均匀的物体中提取3D信息。在同一时期，Wolf方程首次被用于描述与部分相干场相关的传播关联。结合这两个概念，我们提出了Wolf相层析成像（WPT），这是一种利用部分相干场进行衍射层析成像的方法。WPT重建直接在空时域中工作，不需要傅里叶变换，并且将折射率（RI）分布与样品厚度解耦。我们演示了WPT原理使用的数据获得定量相成像方法，升级现有的相对比显微镜通过引入控制相移之间的入射和散射场。WPT中的照明场具有部分空间相干性（从环形瞳孔函数中产生）和低时间相干性（白光），因此，它非常适合Wolf方程。从对应于不同相对比帧的三个强度测量中，通过计算测量的复相关函数的拉普拉斯导数和二阶导数，立即获得三维RI分布。我们通过测量标准样品（微珠）、精子和活神经培养物来验证WPT。该方法的高通量和简单性使其能够研究整个多孔板上活细胞的3D动态事件，RI灵敏度为10（-5）。折射率分析：狼相层析一种确定透明结构的三维折射率分布的方案可以证明对监测活细胞的形态变化是有用的。来自美国伊利诺伊大学的Xi Chen和他的同事说，他们的技术被称为Wolf相位断层扫描（WPT），具有样品制备简单、高通量和高灵敏度的优点（可以检测到10（-5）数量级的折射率变化）。该团队使用WPT分析了几个样品，包括浸泡油中2 μ m聚苯乙烯微球的悬浮液、精子细胞和神经元。该方法利用相衬显微镜和部分相干照明（环形白光源）。生物细胞和组织的折射率映射对癌症和细胞运输和有丝分裂的研究是有用的。
In 1969, Emil Wolf proposed diffraction tomography using coherent holographic imaging to extract 3D information from transparent, inhomogeneous objects. In the same era, the Wolf equations were first used to describe the propagation correlations associated with partially coherent fields. Combining these two concepts, we present Wolf phase tomography (WPT), which is a method for performing diffraction tomography using partially coherent fields. WPT reconstruction works directly in the space-time domain, without the need for Fourier transformation, and decouples the refractive index (RI) distribution from the thickness of the sample. We demonstrate the WPT principle using the data acquired by a quantitative-phase-imaging method that upgrades an existing phase-contrast microscope by introducing controlled phase shifts between the incident and scattered fields. The illumination field in WPT is partially spatially coherent (emerging from a ring-shaped pupil function) and of low temporal coherence (white light), and as such, it is well suited for the Wolf equations. From three intensity measurements corresponding to different phase-contrast frames, the 3D RI distribution is obtained immediately by computing the Laplacian and second time derivative of the measured complex correlation function. We validate WPT with measurements of standard samples (microbeads), spermatozoa, and live neural cultures. The high throughput and simplicity of this method enables the study of 3D, dynamic events in living cells across the entire multiwell plate, with an RI sensitivity on the order of 10(-5). Refractive Index Analysis: Wolf Phase TomographyA scheme for determining the three-dimensional refractive index distribution of transparent structures could prove useful for monitoring morphological changes in living cells. Xi Chen and coworkers from the University of Illinois in the USA say that their technique, called Wolf Phase Tomography (WPT), has the advantages of simple sample preparation, high throughput and also high sensitivity (refractive index variations on the order of 10(-5) can be detected). The team analyzed several samples using WPT including a suspension of 2-mu m polystyrene microspheres in immersion oil, sperm cells and neurons. The approach makes use of an adapted phase-contrast microscope and partially coherent illumination (a ring-shaped white light source). Refractive index mapping of biological cells and tissue is useful for the study of cancer and cellular transport and mitosis.