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Proceedings Paper

Modeling surface plasmon resonance in sensors using finite-difference time-domain analysis
Author(s): Douglas A. Christensen; David Fowers
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Paper Abstract

Surface plasmon resonance (SPR) is currently used as an optical immunassay technique for the detection of various analytes. The uniformity of the metal film and the wavefront structure of the incident beam have an effect on the sensitivity of the SPR technique, yet most analysis methods are not capable of considering inhomogeneous layers or nonplanar excitation beams. We have applied a new numerical electromagnetic method, called finite-difference time- domain (FDTD), to this problem. To correctly model the time domain behavior of the electron oscillations, the dynamic force equation is applied to a Drude free electron model of the metal. We have analyzed a particular SPR configuration consisting of an incident beam of finite size (approximating a focused beam) onto a smooth silver film, and have obtained Poynting vector plots and reflectivity data for this configuration. The angle and magnitude of minimum reflectivity are similar for the FDTD results compared to theoretical predictions, but the angular width of the reflectivity minimum is broadened. We have also analyzed a model of a rough metal film, and find that the local electric fields are enhanced near the metal edges.

Paper Details

Date Published: 28 July 1994
PDF: 7 pages
Proc. SPIE 2131, Biomedical Fiber Optic Instrumentation, (28 July 1994); doi: 10.1117/12.180749
Show Author Affiliations
Douglas A. Christensen, Univ. of Utah (United States)
David Fowers, Univ. of Utah (United States)

Published in SPIE Proceedings Vol. 2131:
Biomedical Fiber Optic Instrumentation
James A. Harrington; David M. Harris; Abraham Katzir; Fred P. Milanovich, Editor(s)

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