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Applied Optics

Applied Optics


  • Vol. 42, Iss. 10 — Apr. 1, 2003
  • pp: 1820–1832

Measuring microscopic viscosity with optical tweezers as a confocal probe

Boaz A. Nemet and Mark Cronin-Golomb  »View Author Affiliations

Applied Optics, Vol. 42, Issue 10, pp. 1820-1832 (2003)

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We demonstrate, what is to the best of our knowledge, a new method for studying the motion of a particle trapped by optical tweezers; in this method the trapping beam itself is used as a confocal probe. By studying the response of the particle to periodic motion of the tweezers, we obtain information about the medium viscosity, particle properties, and trap stiffness. We develop the mathematical model, demonstrate experimentally its validity for our system, and discuss advantages of using this method as a new form of scanning photonic force microscopy for applications in which a high spatial and temporal resolution of the medium viscosity is desired.

© 2003 Optical Society of America

OCIS Codes
(140.7010) Lasers and laser optics : Laser trapping
(170.3880) Medical optics and biotechnology : Medical and biological imaging
(180.1790) Microscopy : Confocal microscopy
(180.5810) Microscopy : Scanning microscopy

Original Manuscript: June 11, 2002
Revised Manuscript: December 2, 2002
Published: April 1, 2003

Boaz A. Nemet and Mark Cronin-Golomb, "Measuring microscopic viscosity with optical tweezers as a confocal probe," Appl. Opt. 42, 1820-1832 (2003)

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