title: Reconfigurable optothermal microparticle trap in air-filled hollow-core photonic crystal fiber.
abstract: We report a novel optothermal trapping mechanism that occurs in air-filled hollow-core photonic crystal fiber. In the confined environment of the core, the motion of a laser-guided particle is strongly influenced by the thermal-gradient-driven flow of air along the core surface. Known as "thermal creep flow," this can be induced either statically by local heating, or dynamically by the absorption (at a black mark placed on the fiber surface) of light scattered by the moving particle. The optothermal force on the particle, which can be accurately measured in hollow-core fiber by balancing it against the radiation forces, turns out to exceed the conventional thermophoretic force by 2 orders of magnitude. The system makes it possible to measure pN-scale forces accurately and to explore thermally driven flow in micron-scale structures.
authors.affiliation: Max Planck Institute for the Science of Light, Guenther-Scharowsky-Straße 1/Bau 24, 91058 Erlangen, Germany.
authors.forename: O A
authors.initials: OA
authors.lastname: Schmidt
authors.forename: M K
authors.initials: MK
authors.lastname: Garbos
authors.forename: T G
authors.initials: TG
authors.lastname: Euser
authors.forename: P St J
authors.initials: PS
authors.lastname: Russell