title: Increasing trap stiffness with position clamping in holographic optical tweezers.
abstract: We present a holographic optical tweezers system capable of position clamping multiple particles. Moving an optical trap in response to the trapped object's motion is a powerful technique for optical control and force measurement. We have now realised this experimentally using a Boulder Nonlinear Systems Spatial Light Modulator (SLM) with a refresh rate of 203Hz. We obtain a reduction of 44% in the variance of the bead's position, corresponding to an increase in effective trap stiffness of 77%. This reduction relies on the generation of holograms at high speed. We present software capable of calculating holograms in under 1ms using a graphics processor unit.
authors.affiliation: Department of Physics and Astronomy, SUPA, University of Glasgow, G12 8QQ, UK. d.preece@physics.gla.ac.uk
authors.forename: Daryl
authors.initials: D
authors.lastname: Preece
authors.forename: Richard
authors.initials: R
authors.lastname: Bowman
authors.forename: Anna
authors.initials: A
authors.lastname: Linnenberger
authors.forename: Graham
authors.initials: G
authors.lastname: Gibson
authors.forename: Steven
authors.initials: S
authors.lastname: Serati
authors.forename: Miles
authors.initials: M
authors.lastname: Padgett
mesh_terms: D017076:Computer-Aided Design; D055119:Elastic Modulus; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006696:Holography / Q000295:instrumentation*; D052898:Optical Tweezers