Trapping is the first as well as the most important step in various optical manipulations. However, when the concentration of sample is extremely low, optical trapping cannot be performed efficiently because the samples are usually out of the action radius of the trapping well. In this paper, numerical simulation results are presented to illustrate an active and efficient optical collection mechanism. We propose the optical collection mechanism by using an array of concentric dielectric rings, in which a series of nanoholes are introduced with optimized separations and radius to form trapping centers. When the incident wavelength is tuned in order, the trapped particles will be transferred from an outer ring to its inner neighboring ring, and finally be collected to the center of the rings. The mechanism reported here paves the way for efficient particle collection, and may find potential applications in various optical manipulations.

捕获是各种光学操作中的第一步，也是最重要的一步。然而，当样品浓度极低时，由于样品通常在捕获井的作用半径之外，因此不能有效地进行光捕获。在本文中，给出了数值模拟结果来说明一种主动有效的光学收集机制。我们通过使用一系列同心电介质环提出了光学收集机制，其中引入了一系列具有优化间隔和半径的纳米孔以形成捕获中心。当入射波长按顺序调谐时，被捕获的粒子将从外环转移到其内相邻环，最后被收集到环的中心。