Paper
16 April 1992 Waveguide ellipsometry biosensors: concept and preliminary analysis
Jinyu Wang
Author Affiliations +
Abstract
The recent use of fiber optic waveguides for biochemical analyses is mainly based on light intensity changes. Waveguide ellipsometry sensors (WEFE) are proposed for biosensor applications. The WEFE is based on the principle of ellipsometry. A laser beam propagates in the waveguide with two fundamental modes: transverse electric field, parallel to and perpendicular to the sensing surface. The evanescent waves interact with the absorbed or conjugated layer of biomolecules, producing changes in the relative phase, (Delta) , and amplitude, (Psi) , upon interaction. The ellipsometric parameters change with biomolecule adsorption or conjugation on the sensing surface. From the ellipsometric parameter changes, the surface concentration, and thus the solution concentration, of the biomolecules can be estimated. Expected advantages of the WEFE are: (1) the WEFE measurement is independent of light intensity; (2) the WEFE measurement is independent of the waveguide coupler quality; (3) (Delta) is very sensitive to the thickness of the adsorbed layer, the WEFE is much more sensitive than sensors based on intensity; (4) optic fibers are commercialized, the WEFE will be easy to fabricate and use commercially. In this paper -- a comparison of WEFE within other biosensors -- the principle of WEFE including light propagation in waveguide and ellipsometry parameter analysis, the WEFE arrangement and instrumentation, and preliminary experimental results are given.
© (1992) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jinyu Wang "Waveguide ellipsometry biosensors: concept and preliminary analysis", Proc. SPIE 1648, Fiber Optic Medical and Fluorescent Sensors and Applications, (16 April 1992); https://doi.org/10.1117/12.58286
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KEYWORDS
Waveguides

Sensors

Ellipsometry

Fiber optics sensors

Biological research

Fiber optics

Refractive index

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