基于径向偏振光束的微粒捕获与操控

Trapping and manipulation of microparticles using radially polarized beams

因为空间变化的偏振分布及独特的聚焦特性,径向偏振光束在粒子捕获及操控方面有独特的应用价值。从理论和实验方面研究了基于径向偏振光束的微粒捕获与操控。首先,介绍了捕获力的计算方法,重点基于光线理论模型计算了径向偏振光束的轴向及横向捕获效率,并与切向偏振光和圆偏振光的捕获效率进行了比较;然后,基于倒置显微镜和空间光调制器搭建了光学捕获与操控系统,采用两种不同的成像物镜实现了对直径为10μm左右的酵母菌细胞及直径为1μm的苯乙烯小球的捕获和操控,根据预定的轨迹实现了粒子的稳定移动,体现了该类型光镊较为宽阔的应用前景;最后,简要分析了影响粒子捕获及操控的若干因素,为系统改进提供了指导意见。

Due to space-variant polarization distribution and unique focusing properties, the radially polarized beam （RPB） is presented unique application in trapping and manipulation of microparticles. The cell trapping and manipulation using RPBS is studied theoretically and experimentally in the paper. First, the calculation methods of trapping force are introduced, and longitudinal and transverse trapping efficiencies using RPBs are calculated using geometric ray model, which are further compared with those using azimuthally polarized beam and circularly polarized beam. Then, an optical trapping and manipulation system based on an inverted microscopy and a spatial light modulator is built up, and yeast cells （ - 10 μm） and phenylethylene particles （ - 1μm） are trapped and manipulated using two different objective lens, and the trapped cells can be shifted according to the designed trace, which presents wider applications of such optical tweezers. Finally, some factors affecting the trapping and manipulation of cells are further analyzed, which will provide some basic guidelines for the system improvement.