title: Passive torque wrench and angular position detection using a single-beam optical trap.
abstract: The recent advent of angular optical trapping techniques has allowed for rotational control and direct torque measurement on biological substrates. Here we present a method that increases the versatility and flexibility of these techniques. We demonstrate that a single beam with a rapidly rotating linear polarization can be utilized to apply a constant controllable torque to a trapped particle without active feedback, while simultaneously measuring the particle angular position. In addition, this device can rapidly switch between a torque wrench and an angular trap. These features should make possible torsional measurements across a wide range of biological systems.
authors.affiliation: Department of Physics, Laboratory of Atomic and Solid State Physics, Cornell University, Ithaca, New York 14853, USA.
authors.forename: James
authors.initials: J
authors.lastname: Inman
authors.forename: Scott
authors.initials: S
authors.lastname: Forth
authors.forename: Michelle D
authors.initials: MD
authors.lastname: Wang
mesh_terms: D052898:Optical Tweezers; D012399:Rotation
references.citation: Faraday Discuss. 2008;137:319-33; discussion 403-24
references.pmid: 18214111
references.citation: Science. 1998 Oct 30;282(5390):902-7
references.pmid: 9794753
references.citation: Science. 2001 May 4;292(5518):912-4
references.pmid: 11340200
references.citation: Opt Express. 2002 Sep 23;10(19):984-9
references.pmid: 19451954
references.citation: Phys Rev Lett. 2004 May 14;92(19):190801
references.pmid: 15169392
references.citation: Phys Rev Lett. 2008 Apr 11;100(14):148301
references.pmid: 18518075
references.citation: Opt Lett. 2009 Jan 15;34(2):139-41
references.pmid: 19148234
references.citation: Phys Chem Chem Phys. 2009 Jun 28;11(24):4800-3
references.pmid: 19506753
references.citation: Opt Express. 2003 Mar 10;11(5):446-51
references.pmid: 19461751
references.citation: Nature. 2003 Jan 23;421(6921):423-7
references.pmid: 12540915
references.citation: Nat Methods. 2007 Mar;4(3):223-5
references.pmid: 17322891