Surface plasmon resonance based sensing of aqueous solutions using spectral interferometry
- Publisher: Polish Institute of Physics
This paper deals with a polarimetric setup to measure the refractive index change of aqueous solutions.
The experimental method is based on the surface plasmon resonance effect in the Kretschmann configuration
combined with spectral interferometry. In order to retrieve surface plasmon resonance-induced differential phase
change, a windowed Fourier transform was adopted to extract the phases from two spectral interferograms, one
corresponding to the reference material (air) and the second to the analyte (NaCl aqueous solution). The shift of
phase curve is related to the analyte refractive index change. The refractive index of the NaCl aqueous solutions
(0, 2 and 5 percent) was measured by the Abbe refractometer at a wavelength of 589.3 nm and compared with
theoretical one, calculated by the Lorentz–Lorenz equation. An excellent agreement between the values was
confirmed. The resonance wavelengths as extremes of the surface plasmon resonance-induced differential phase
changes retrieved from spectral interference signals were compared with the resonance wavelengths determined
from spectral reflectance measurements. A good agreement between the values was confirmed.
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