Zhang Yuquan, Shen Junfeng, Min Changjun, Jin Yunfeng, Jiang Yuqiang, Liu Jun, Zhu Siwei, Sheng Yunlong, Zayats Anatoly V, Yuan Xiaocong
Nanophotonics Research Center , Shenzhen University , Shenzhen 518060 , China.
College of Physics and Technology , Southwest Jiaotong University , Chengdu , 614200 , China.
Nano Lett. 2018 Sep 12;18(9):5538-5543. doi: 10.1021/acs.nanolett.8b01929. Epub 2018 Aug 13.
Optical trapping and manipulation of atoms, nanoparticles, and biological entities are widely employed in quantum technology, biophysics, and sensing. Single traps are typically achieved with linearly polarized light, while vortex beams form rotationally unstable symmetric traps. Here we demonstrate multiplexed optical traps reconfigurable with intensity and polarization of the trapping beam using intensity-dependent polarizability of nanoparticles. Nonlinearity combined with a longitudinal field of focused femtosecond vortex beams results in a stable optical force potential with multiple traps, in striking contrast to a linear trapping regime. The number of traps and their orientation can be controlled by the cylindrical vector beam order, polarization, and intensity. The nonlinear trapping demonstrated here on the example of plasmonic nanoparticles opens up opportunities for deterministic trapping and polarization-controlled manipulation of multiple dielectric and semiconductor particles, atoms, and biological objects since most of them exhibit a required intensity-dependent refractive index.
原子、纳米颗粒和生物实体的光镊捕获及操控在量子技术、生物物理学和传感领域得到了广泛应用。单光阱通常由线偏振光实现，而涡旋光束会形成旋转不稳定的对称光阱。在此，我们利用纳米颗粒的强度依赖极化率，展示了可通过捕获光束的强度和偏振进行重构的复用光阱。与线性捕获机制形成鲜明对比的是，非线性与聚焦飞秒涡旋光束的纵向场相结合，产生了具有多个光阱的稳定光力势。光阱的数量及其取向可通过柱矢量光束阶数、偏振和强度来控制。本文以等离子体纳米颗粒为例展示的非线性捕获，为确定性捕获以及对多个介电和半导体颗粒、原子及生物物体进行偏振控制的操控开辟了机会，因为它们中的大多数都表现出所需的强度依赖折射率。
