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Journal of the Optical Society of America B

Journal of the Optical Society of America B


  • Editor: Henry van Driel
  • Vol. 28, Iss. 10 — Oct. 1, 2011
  • pp: 2369–2373

Nonconservative forcing and diffusion in refractive optical traps

Ingmar Saberi and Fred Gittes  »View Author Affiliations

JOSA B, Vol. 28, Issue 10, pp. 2369-2373 (2011)

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Refractive optical trapping forces can be nonconservative in the vicinity of a stable equilibrium point even in the absence of radiation pressure. We discuss how nonconservative 3D force fields reduce, near an equilibrium point, to circular forcing in a plane; a simple model of such forcing is the refractive trapping of a sphere by four rays. We discuss in general the diffusion of an anisotropically trapped, circularly forced particle and obtain its spectrum of motion. Equipartition of potential energy holds, even though the nonconservative flow does not follow equipotentials of the trap. We find that the dissipated nonconservative power is proportional to temperature, providing a mechanism for runaway heating instability in traps.

© 2011 Optical Society of America

OCIS Codes
(000.6590) General : Statistical mechanics
(080.2730) Geometric optics : Matrix methods in paraxial optics
(140.7010) Lasers and laser optics : Laser trapping
(350.4855) Other areas of optics : Optical tweezers or optical manipulation

ToC Category:
Lasers and Laser Optics

Original Manuscript: June 9, 2011
Manuscript Accepted: July 22, 2011
Published: September 6, 2011

Virtual Issues
Vol. 6, Iss. 11 Virtual Journal for Biomedical Optics
February 6, 2012 Spotlight on Optics

Ingmar Saberi and Fred Gittes, "Nonconservative forcing and diffusion in refractive optical traps," J. Opt. Soc. Am. B 28, 2369-2373 (2011)

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