title: Optical force field mapping in microdevices.
abstract: We present a method for characterizing microscopic optical force fields. Two dimensional vector force maps are generated by measuring the optical force applied to a probe particle for a grid of particle positions. The method is used to map out the force field created by the beam from a lensed fiber inside a liquid filled microdevice. We find transverse gradient forces and axial scattering forces on the order of 2 pN per 10 mW laser power which are constant over a considerable axial range (>35 microm). These findings suggest future useful applications of lensed fibers for particle guiding/sorting. The propulsion of a small particle at a constant velocity of 200 microm s(-1) is shown.
authors.affiliation: Centre for Biophotonics and Laser Science, School of Physical Sciences, The University of Queensland, Brisbane 4072, QLD, Australia. knoener@physics.uq.edu.au
authors.forename: Gregor
authors.initials: G
authors.lastname: Knöner
authors.forename: Adrian
authors.initials: A
authors.lastname: Ratnapala
authors.forename: Timo A
authors.initials: TA
authors.lastname: Nieminen
authors.forename: Chris J
authors.initials: CJ
authors.lastname: Vale
authors.forename: Norman R
authors.initials: NR
authors.lastname: Heckenberg
authors.forename: Halina
authors.initials: H
authors.lastname: Rubinsztein-Dunlop
mesh_terms: D007834:Lasers; D008855:Microscopy, Electron, Scanning / Q000295:instrumentation / Q000379:methods; D055095:Optics and Photonics; D012680:Sensitivity and Specificity