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Title: Absolute calibration of optical tweezers

As a step toward absolute calibration of optical tweezers, a first-principles theory of trapping forces with no adjustable parameters, corrected for spherical aberration, is experimentally tested. Employing two very different setups, we find generally very good agreement for the transverse trap stiffness as a function of microsphere radius for a broad range of radii, including the values employed in practice, and at different sample chamber depths. The domain of validity of the WKB ('geometrical optics') approximation to the theory is verified. Theoretical predictions for the trapping threshold, peak position, depth variation, multiple equilibria, and 'jump' effects are also confirmed.
Authors:
; ; ; ; ;  [1] ;  [2]
  1. LPO-COPEA and Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, 21941-590 (Brazil)
  2. (Brazil)
Publication Date:
OSTI Identifier:
20779136
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 88; Journal Issue: 13; Other Information: DOI: 10.1063/1.2189148; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; APPROXIMATIONS; CALIBRATION; FLEXIBILITY; GEOMETRICAL ABERRATIONS; OPTICS; TRAPPING; TRAPS