Quantitative phase imaging (QPI) of transparent samples plays an essential role in multiple biomedical applications, and miniaturizing these systems will enable their adoption into point-of-care and in vivo applications. Here, we propose a compact quantitative phase gradient microscope (QGPM) based on two dielectric metasurface layers, inspired by a classical differential interference contrast (DIC) microscope. Owing to the multifunctionality and compactness of the dielectric metasurfaces, the QPGM simultaneously captures three DIC images to generate a quantitative phase gradient image in a single shot. The volume of the metasurface optical system is on the order of 1 mm³. Imaging experiments with various phase resolution samples verify the capability to capture quantitative phase gradient data, with phase gradient sensitivity better than 92.3 mrad μm⁻¹ and single-cell resolution. The results showcase the potential of metasurfaces for developing miniaturized QPI systems for label-free cellular imaging and point-of-care devices.

透明样品的定量相成像（QPI）在多种生物医学应用中起着至关重要的作用，而将这些系统小型化将使其能够应用于即时医疗和体内应用。在这里，我们基于经典的微分干涉对比（DIC）显微镜，提出了一种基于两个介电超表面层的紧凑型定量相梯度显微镜（QGPM）。由于介电超表面的多功能性和紧凑性，QPGM可一次捕获三张DIC图像，以生成定量的相位梯度图像。超表面光学系统的体积约为1 mm ³。具有各种相位分辨率样品的成像实验证明了捕获定量相位梯度数据的能力，其相位梯度灵敏度优于92.3 mradμm ^-1，并且具有单细胞分辨率。结果显示超表面在开发用于无标签细胞成像和即时护理设备的小型QPI系统方面的潜力。