The past two decades have witnessed the revolutionary development of optical trapping of nanoparticles, most of which deal with trapping stiffness larger than 10^-8 N/m. In this conventional regime, however, it remains a formidable challenge to sort out sub-50-nm nanoparticles with single-nanometer precision, isolating us from a rich flatland with advanced applications of micromanipulation. With an insightfully established roadmap of damping, the synchronization between optical force and flow drag force can be coordinated to attempt the loosely overdamped realm (stiffness, 10^-10 to 10^-8 N/m), which has been challenging. This paper intuitively demonstrates the remarkable functionality to sort out single gold nanoparticles with radii ranging from 30 to 50 nm, as well as 100- and 150-nm polystyrene nanoparticles, with single nanometer precision. The quasi-Bessel optical profile and the loosely overdamped potential wells in the microchannel enable those aforementioned nanoparticles to be separated, positioned, and microscopically oscillated. This work reveals an unprecedentedly meaningful damping scenario that enriches our fundamental understanding of particle kinetics in intriguing optical systems, and offers new opportunities for tumor targeting, intracellular imaging, and sorting small particles such as viruses and DNA.

中文翻译：

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纳米精度的线性分选，具有同步的光流体双壁垒。

在过去的二十年中，见证了纳米粒子光学捕集技术的革命性发展，其中大多数处理捕集刚度大于10 ^-8 N / m。然而，在这种常规方式下，以单纳米精度挑选出低于50 nm的纳米颗粒仍然是一项艰巨的挑战，要使我们与微操作的先进应用隔离在丰富的平坦土地上。借助有见地的阻尼路线图，可以协调光学力和流动阻力之间的同步，以尝试松散过度阻尼的领域（刚度为10 ^-10到10 ^-8N / m），这非常具有挑战性。本文直观地展示了卓越的功能，可以以单纳米精度分选半径为30至50 nm的单个金纳米颗粒以及100和150 nm的聚苯乙烯纳米颗粒。准贝塞尔光学轮廓和微通道中的松散过度阻尼的势阱使上述那些纳米颗粒得以分离，定位和微观振荡。这项工作揭示了一个前所未有的有意义的阻尼场景，该场景丰富了我们对有趣的光学系统中粒子动力学的基本理解，并为肿瘤靶向，细胞内成像以及对诸如病毒和DNA之类的小粒子进行分类提供了新的机会。