title: Selective trapping or rotation of isotropic dielectric microparticles by optical near field in a plasmonic archimedes spiral.
abstract: We demonstrate selective trapping or rotation of optically isotropic dielectric microparticles by plasmonic near field in a single gold plasmonic Archimedes spiral. Depending on the handedness of circularly polarized excitation, plasmonic near fields can be selectively engineered into either a focusing spot for particle trapping or a plasmonic vortex for particle rotation. Our design provides a simple solution for subwavelength optical manipulation and may find applications in micromechanical and microfluidic systems.
authors.affiliation: Institute of Photonics Technologies, ‡Department of Chemistry, §Center for Nanotechnology, Materials Sciences, and Microsystems, and ∥Frontier Research Center on Fundamental and Applied Science of Matters, National Tsing Hua University , Hsinchu 30013, Taiwan.
authors.forename: Wei-Yi
authors.initials: WY
authors.lastname: Tsai
authors.forename: Jer-Shing
authors.initials: JS
authors.lastname: Huang
authors.forename: Chen-Bin
authors.initials: CB
authors.lastname: Huang