Optical trapping has become a powerful tool in numerous fields such as biology, physics, chemistry, etc. In standard optical trapping systems, trapping and imaging shares the same objective lens, confining the region of observation to the focal plane. To capture optical trapping processes occurring in other plane, especially the axial plane, many methods have been proposed to achieve this goal. Here, we review the methods of acquiring the axial-plane information from which axial plane trapping is observed and discuss their advantages and limitations. To overcome the limitations existing in these methods, we developed an optical tweezer system that allows for simultaneous optical trapping and imaging technique. The versatility and usefulness of the system in axial-plane trapping and imaging is demonstrated by investigating its trapping performance with various optical fields, including Bessel, Airy and snake-like beams. The potential applications of the proposed technique are suggested to several fields, including optical pulling, longitudinal optical binding, tomographic phase microscopy and superresolution microscopy.

中文翻译：

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轴向平面中的同时光学俘获和成像：当前进展的回顾

光学诱捕已成为生物学、物理学、化学等众多领域的有力工具。在标准光学诱捕系统中，诱捕和成像共享同一物镜，将观察区域限制在焦平面上。为了捕获发生在其他平面，尤其是轴平面上的光学俘获过程，已经提出了许多方法来实现这一目标。在这里，我们回顾了获取轴向平面信息的方法，从中可以观察到轴向平面陷阱，并讨论它们的优点和局限性。为了克服这些方法中存在的局限性，我们开发了一种允许同时进行光学捕获和成像技术的光镊系统。该系统在轴平面捕获和成像方面的多功能性和实用性通过研究其在各种光场（包括贝塞尔、艾里和蛇形光束）下的捕获性能来证明。所提出的技术的潜在应用被建议到几个领域，包括光学牵引、纵向光学结合、断层扫描相位显微镜和超分辨率显微镜。