光学镊子
等离子体子
俘获
镊子
光学力
散射
材料科学
压力梯度力
粒子(生态学)
米氏散射
数值孔径
联轴节(管道)
光学
光圈(计算机存储器)
表面等离子体子
光散射
分子物理学
物理
光电子学
波长
生态学
海洋学
生物
地质学
声学
冶金
作者
Changjun Min,Zhe Shen,Junfeng Shen,Yuquan Zhang,Hui Fang,Guanghui Yuan,Luping Du,Siwei Zhu,Ting Lei,Xiaocong Yuan
摘要
Scattering forces in focused light beams push away metallic particles. Thus, trapping metallic particles with conventional optical tweezers, especially those of Mie particle size, is difficult. Here we investigate a mechanism by which metallic particles are attracted and trapped by plasmonic tweezers when surface plasmons are excited and focused by a radially polarized beam in a high-numerical-aperture microscopic configuration. This contrasts the repulsion exerted in optical tweezers with the same configuration. We believe that different types of forces exerted on particles are responsible for this contrary trapping behaviour. Further, trapping with plasmonic tweezers is found not to be due to a gradient force balancing an opposing scattering force but results from the sum of both gradient and scattering forces acting in the same direction established by the strong coupling between the metallic particle and the highly focused plasmonic field. Theoretical analysis and simulations yield good agreement with experimental results. Focused light beams can be used as optical tweezers for manipulating small dielectric particles, but they normally repel metallic ones. By exploiting surface plasmons excited by a radially polarized beam, Min et al.show that it is possible to trap metallic particles with diameters up to 2.2 μm.
科研通智能强力驱动
Strongly Powered by AbleSci AI