title: Low-power nano-optical vortex trapping via plasmonic diabolo nanoantennas.
abstract: Optical vortex trapping can allow the capture and manipulation of micro- and nanometre-sized objects such as damageable biological particles or particles with a refractive index lower than the surrounding material. However, the quest for nanometric optical vortex trapping that overcomes the diffraction limit remains. Here we demonstrate the first experimental implementation of low-power nano-optical vortex trapping using plasmonic resonance in gold diabolo nanoantennas. The vortex trapping potential was formed with a minimum at 170 nm from the central local maximum, and allowed polystyrene nanoparticles in water to be trapped strongly at the boundary of the nanoantenna. Furthermore, a large radial trapping stiffness, ~0.69 pN nm(-1) W(-1), was measured at the position of the minimum potential, showing good agreement with numerical simulations. This subwavelength-scale nanoantenna system capable of low-power trapping represents a significant step toward versatile, efficient nano-optical manipulations in lab-on-a-chip devices.
authors.affiliation: Department of Physics, Korea University, Seoul 136-701, South Korea.
authors.forename: Ju-Hyung
authors.initials: JH
authors.lastname: Kang
authors.forename: Kipom
authors.initials: K
authors.lastname: Kim
authors.forename: Ho-Seok
authors.initials: HS
authors.lastname: Ee
authors.forename: Yong-Hee
authors.initials: YH
authors.lastname: Lee
authors.forename: Tae-Young
authors.initials: TY
authors.lastname: Yoon
authors.forename: Min-Kyo
authors.initials: MK
authors.lastname: Seo
authors.forename: Hong-Gyu
authors.initials: HG
authors.lastname: Park
mesh_terms: D055590:Electromagnetic Phenomena; D006046:Gold / Q000737:chemistry; D056656:Lab-On-A-Chip Devices; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D052898:Optical Tweezers; D010316:Particle Size; D017785:Photons; D011137:Polystyrenes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D014867:Water
chemical_list: D011137:Polystyrenes; D014867:Water; D006046:Gold; D012822:Silicon Dioxide