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Proceedings Paper

Guiding and trapping microparticles in an extended surface field
Author(s): Veneranda Garces-Chavez; Gabriel C. Spalding; Kishan Dholakia
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Paper Abstract

We made use of near-field photonic forces in order to manipulate and trap microparticles in an extended area above a solid surface. Structures in evanescent field were created either by imaging a Ronchi ruler (fringe structure) or by focusing five beams (spot structure) at the top of a prism. The surface field couples to microparticles in close proximity, where the near-field wave can be converted to a propagating wave, via photon tunnelling across the gap from prism to microparticles. Due to transverse optical gradients and radiation pressure, microparticles immersed in water were laterally trapped and longitudinally guided along the direction of the evanescent waves. By splitting the laser beam into two equal counterpropagating beams, another evanescent wave was created exactly with the same structure in the opposite direction to the first one. We use this geometry we demonstrate stably trap of thousand of microparticles over an area of about a millimetre squared. Red blood and yeast cells were also individually trapped in an array of potential wells. We believe this is the first demonstration of guiding and, separately, trapped in unison multiple microparticles on a surface.

Paper Details

Date Published: 18 October 2004
PDF: 9 pages
Proc. SPIE 5514, Optical Trapping and Optical Micromanipulation, (18 October 2004); doi: 10.1117/12.559428
Show Author Affiliations
Veneranda Garces-Chavez, Univ. of St. Andrews (United Kingdom)
Gabriel C. Spalding, Illinois Wesleyan Univ. (United States)
Kishan Dholakia, Univ. of St. Andrews (United Kingdom)

Published in SPIE Proceedings Vol. 5514:
Optical Trapping and Optical Micromanipulation
Kishan Dholakia; Gabriel C. Spalding, Editor(s)

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