Trapping and manipulating micro-objects and achieving high-precision measurements of tiny forces and displacements are of paramount importance in both physical and biological research. While conventional optical tweezers rely on tightly focused beams generated by bulky microscope systems, the emergence of flat lenses, particularly metalenses, has revolutionized miniature optical tweezers applications. In contrast to traditional objectives, the metalenses can be seamlessly integrated into sample chambers, facilitating flat-optics-based light manipulation. In this study, we propose an experimentally realized transmissive and polarization-insensitive water-immersion metalens, constructed using adaptive nano-antennas. This metalens boasts an ultra-high numerical aperture of 1.28 and achieves a remarkable focusing efficiency of approximately 50 % at a wavelength of 532 nm. Employing this metalens, we successfully demonstrate stable optical trapping, achieving lateral trapping stiffness exceeding 500 pN/(μm W). This stiffness magnitude aligns with that of conventional objectives and surpasses the performance of previously reported flat lenses. Furthermore, our bead steering experiment showcases a lateral manipulation range exceeding 2 μm, including a region of around 0.5 μm exhibiting minimal changes in stiffness for smoothly optical manipulation. We believe that this metalens paves the way for flat-optics-based optical tweezers, simplifying and enhancing optical trapping and manipulation processes, attributing ease of use, reliability, high performance, and compatibility with prevalent optical tweezers applications, including single-molecule and single-cell experiments.

中文翻译：

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使用透射且偏振不敏感的超透镜进行光捕获和操纵

捕获和操纵微观物体以及实现微小力和位移的高精度测量在物理和生物研究中都至关重要。虽然传统的光镊依赖于笨重的显微镜系统产生的紧密聚焦的光束，但平面透镜（尤其是超透镜）的出现彻底改变了微型光镊的应用。与传统物镜相比，超透镜可以无缝集成到样品室中，从而促进基于平面光学的光操纵。在这项研究中，我们提出了一种通过实验实现的透射且偏振不敏感的水浸超透镜，使用自适应纳米天线构建。该超透镜拥有 1.28 的超高数值孔径，在 532 nm 波长下可实现约 50% 的卓越聚焦效率。利用这种超透镜，我们成功地展示了稳定的光学捕获，实现了超过 500 pN/(μm W) 的横向捕获刚度。这种刚度大小与传统物镜的刚度大小一致，并且超越了之前报道的平面透镜的性能。此外，我们的珠子转向实验展示了超过 2 μm 的横向操纵范围，包括 0.5 μm 左右的区域，表现出最小的刚度变化，可实现平滑的光学操纵。我们相信，这种超透镜为基于平面光学的光镊铺平了道路，简化和增强了光捕获和操纵过程，具有易用性、可靠性、高性能以及与流行的光镊应用（包括单分子和单分子）的兼容性。 -细胞实验。