The University of Memphis, Department of Electrical and Computer Engineering, Memphis, Tennessee 381, USA.
Universidad Nacional de Colombia Sede Medellin, School of Physics, Medellin, Colombia.
J Biomed Opt. 2020 Aug;25(8):1-11. doi: 10.1117/1.JBO.25.8.086501.
The hallmarks of digital holographic microscopy (DHM) compared with other quantitative phase imaging (QPI) methods are high speed, accuracy, spatial resolution, temporal stability, and polarization-sensitivity (PS) capability. The above features make DHM suitable for real-time quantitative PS phase imaging in a broad number of biological applications aimed at understanding cell growth and dynamic changes occurring during physiological processes and/or in response to pharmaceutical agents.
The insertion of a Fresnel biprism (FB) in the image space of a light microscope potentially turns any commercial system into a DHM system enabling QPI with the five desired features in QPI simultaneously: high temporal sensitivity, high speed, high accuracy, high spatial resolution, and PS. To the best of our knowledge, this is the first FB-based DHM system providing these five features all together.
The performance of the proposed system was calibrated with a benchmark phase object. The PS capability has been verified by imaging human U87 glioblastoma cells.
The proposed FB-based DHM system provides accurate phase images with high spatial resolution. The temporal stability of our system is in the order of a few nanometers, enabling live-cell studies. Finally, the distinctive behavior of the cells at different polarization angles (e.g., PS capability) can be observed with our system.
We have presented a method to turn any commercial light microscope with monochromatic illumination into a PS QPI system. The proposed system provides accurate quantitative PS phase images in a new, simple, compact, and cost-effective format, thanks to the low cost (a few hundred dollars) involved in implementing this simple architecture, enabling the use of this QPI technique accessible to most laboratories with standard light microscopes.
与其他定量相衬成像（QPI）方法相比，数字全息显微镜（DHM）的特点是速度快、精度高、空间分辨率高、时间稳定性好和偏振灵敏度（PS）能力。上述特点使 DHM 适用于实时定量 PS 相衬成像，广泛应用于旨在了解细胞生长和生理过程中发生的动态变化或对药物反应的许多生物学应用。
在光学显微镜的像空间中插入菲涅耳双棱镜（FB），可将任何商业系统变成 DHM 系统，同时具有 QPI 的五个期望特性：高时间灵敏度、高速、高精度、高空间分辨率和 PS。据我们所知，这是第一个提供所有这五个特性的基于 FB 的 DHM 系统。
用基准相衬物体对所提出的系统进行性能校准。通过对人 U87 神经胶质瘤细胞成像验证了 PS 能力。
所提出的基于 FB 的 DHM 系统提供了具有高空间分辨率的准确相位图像。我们系统的时间稳定性在纳米级范围内，能够进行活细胞研究。最后，可以用我们的系统观察到细胞在不同偏振角下的独特行为（例如，PS 能力）。
我们提出了一种将任何具有单色照明的商用显微镜变成 PS QPI 系统的方法。由于实施这种简单架构的成本低（几百美元），所提出的系统以新的、简单、紧凑和具有成本效益的格式提供了准确的定量 PS 相衬图像，使具有标准显微镜的大多数实验室都可以使用这种 QPI 技术。
