title: Optical transport, lifting and trapping of micro-particles by planar waveguides.
abstract: Optical waveguides can be used to trap and transport micro-particles. The particles are held close to the waveguide surface by the evanescent field and propelled forward. We propose a new technique to lift and trap particles above the surface of the waveguides. This is made possible by a gap between two opposing, planar waveguides. The field emitted from each of the waveguide ends diverge fast, away from the substrate and into the cover-medium. By combining two fields propagating at an angle upwards and coming from opposite sides of a gap, particles can be stably lifted and trapped at the crossing of the two fields. Thus, particles are transported by waveguides leading to a gap, where they are lifted away from the substrate and trapped. The experiments are supported by numerical simulations of the forces on the micro-particles. Fluorescence imaging is used to track the particles in 3D with a precision of 50 nm.
authors.forename: Øystein Ivar
authors.initials: ØI
authors.lastname: Helle
authors.forename: Balpreet Singh
authors.initials: BS
authors.lastname: Ahluwalia
authors.forename: Olav Gaute
authors.initials: OG
authors.lastname: Hellesø