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Proceedings Paper

Colloidal crystallization induced by optical gradient forces exerted by optical tweezers
Author(s): Dirk L. J. Vossen; Myrthe A. Plaisier; Alfons van Blaaderen
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Paper Abstract

Optical tweezers were used to crystallize colloidal dispersions without manipulating colloids on a single particle level. Using "optical gradient" or "high-frequency dielectrophoretic" forces, we demonstrate control over local particle concentration. This control can be used to induce crystallization and melting in two- and three-dimensional colloidal dispersions using single beam gradient optical tweezers. In our setup, two microscope objectives (one above and one below the sample) allow independent three-dimensional manipulation and imaging of the structure formation inside the sample. We demonstrate crystallization near a wall for a range of particles sizes, refractive index contrasts and numerical apertures. In a colloidal mixture of tracer particles with a high refractive index core and low refractive index host spheres dispersed in a host refractive index matching solvent, control over the tracers can indirectly lead to controlled crystallization of the host particles.

Paper Details

Date Published: 18 October 2004
PDF: 8 pages
Proc. SPIE 5514, Optical Trapping and Optical Micromanipulation, (18 October 2004); doi: 10.1117/12.558923
Show Author Affiliations
Dirk L. J. Vossen, Univ. Utrecht (Netherlands)
Myrthe A. Plaisier, Univ. Utrecht (Netherlands)
Alfons van Blaaderen, Univ. Utrecht (Netherlands)

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

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