Abstract. Lensless microscopes are simple, portable, and cost effective compared with the sophisticated microscopes of today that require high-end objectives, lenses, and filters. We demonstrate a lensless on-chip phase microscope based on the holographic principle to image 3D nanometric depth information from transparent and weakly scattering biological samples. We characterize the microscope using standard quantitative phase resolution target (PRT) charts with feature depths from 50 to 350 nm and report a signal-to-noise ratio value of 23 dB. Further, we apply a gradient descent-based constrained optimization approach for phase retrieval to eliminate the twin image and noise from the hologram. The device, operating as an inline holographic microscope, can perform quantitative phase imaging with nanometric depth sensitivity for a field of view of 29.4 mm2 using an LED-based light source butt-coupled to an optical fiber cable.

中文翻译：

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使用低成本片上无透镜在线全息显微镜进行纳米深度相位成像

摘要。与当今需要高端物镜、镜头和滤光片的精密显微镜相比，无镜头显微镜简单、便携且具有成本效益。我们展示了一种基于全息原理的无透镜片上相位显微镜，可从透明和弱散射生物样品中成像 3D 纳米深度信息。我们使用特征深度为 50 到 350 nm 的标准定量相位分辨率目标 (PRT) 图表来表征显微镜，并报告了 23 dB 的信噪比值。此外，我们应用基于梯度下降的约束优化方法进行相位检索，以消除全息图中的孪生图像和噪声。该设备作为在线全息显微镜运行，