J Opt Soc Am A Opt Image Sci Vis. 2022 Aug 1;39(8):1371-1377. doi: 10.1364/JOSAA.462817.
The identification and separation of chiral substances are of importance in the biological, chemical, and pharmaceutical industries. Here, we demonstrate that a focused circularly polarized vortex beam can, in the focal plane, selectively trap and rotate chiral dipolar particles via radial and azimuthal optical forces. The handedness and topological charge of the incident beam have strong influence on identifying and separating behavior: left- and right-handed circular polarizations lead to opposite effects on the particle of trapping and rotating, while the sign of topological charge will change the particle's rotation direction. Such effects are a direct result of the handedness and topological charge manifesting themselves in the directions of the spin angular momentum (SAM) and Poynting vector. The research provides insight into the chiral light-matter interaction and may find potential application in the identification and separation of chiral nanoparticles.
手性物质的识别和分离在生物、化学和制药行业中具有重要意义。在这里，我们证明了聚焦的圆偏振涡旋光束可以在焦平面上通过径向和角向光学力选择性地捕获和旋转手性偶极粒子。入射光束的手性和拓扑电荷对识别和分离行为有很强的影响：左旋和右旋圆偏振光对粒子的捕获和旋转有相反的影响，而拓扑电荷的符号会改变粒子的旋转方向。这种效应是手性和拓扑电荷在手性角动量（SAM）和坡印廷矢量的方向上表现出来的直接结果。该研究为手性光物质相互作用提供了新的认识，并可能在手性纳米粒子的识别和分离方面有潜在的应用。
