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Proceedings Paper

Microphotography of an electrodynamically levitated microparticle
Author(s): Stephen Arnold; Lorcan M. Folan
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Paper Abstract

An electrodynamic levitator-trap (Paul trap) is used at line frequency (i.e. 60 Hz) as a sample cell for the long term microphotography of a microparticle in air at STP. Images are obtained in a trap modified to eliminate stray static fields at its AC 'null' point. Resolution in these long term images is found to be limited principally by stochastic thermal fluctuations and optical diffraction. A stochastic differential equation constructed for describing the particle's motion is found to be in good agreement with imaging experiments. This model provides an optimal limit to which a particle may be localized by increasing the drive potential, and indicates that this limit is a function principally of particle size and temperature. Images taken in fluorescence from a glycerol particle containing a probable surfactant are presented. Polarization resolution of these images clearly shows segregation of the molecule to the surface and identifies the orientation of the molecular emission moment in relation to the surface normal.

Paper Details

Date Published: 24 May 1993
PDF: 5 pages
Proc. SPIE 1862, Laser Applications in Combustion and Combustion Diagnostics, (24 May 1993); doi: 10.1117/12.145698
Show Author Affiliations
Stephen Arnold, Polytechnic Univ. (United States)
Lorcan M. Folan, Polytechnic Univ. (United States)

Published in SPIE Proceedings Vol. 1862:
Laser Applications in Combustion and Combustion Diagnostics
Larry C. Liou, Editor(s)

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