Spatial measurement of spurious forces with optical tweezers

Date
2013
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Source Title
Proceedings of SPIE Vol. 8785, 8th Iberoamerican Optics Meeting and 11th Latin American Meeting on Optics, Lasers, and Applications, 2013
Print ISSN
0277-786X
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Publisher
SPIE
Volume
8785
Issue
Pages
1 - 7
Language
English
Type
Conference Paper
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Abstract

The study of diffusion in a crowded and complex environment, such as inside a cell or within a porous medium, is of fundamental importance for science and technology. Combining blinking holographic optical tweezers and sub-pixel video microscopy permits one to study Brownian motion in confined geometries. In this work, in particular, we have studied the Brownian motion of two colloidal particles interacting hydrodynamically with each other. The proximity between the two microspheres induces a space-dependence in the particles diffusion coefficient and, therefore, a spurious drift. We measure this drift and evaluate the magnitude of the spurious force associated with it. We present the optoelectronic tools employed in the experiment and we discuss the experimental results.

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Keywords
Blinking optical tweezers, Brownian motion, Diffusion gradients, Digital video microscopy, Holographic optical tweezers, Stochastic differential equations
Citation
Published Version (Please cite this version)