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Abstract
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We used the finite difference time domain method to calculate scattering spectra
for a multilayer nanoshell (MNS) consisting of a gold core, amolecular layer and a gold shell.
The effects of geometrical parameters of the multilayer nanoshell (MNS) such as size, aspect
ratio, the thickness of the shell and middle layer on the scattering properties of the MNS are
investigated. We have also studied the plasmon-exciton coupling. In order to determine the
coupling region, our numerical data are fitted to the coupled oscillator model. According to
the obtained results, the plasmon-exciton coupling is found in the intermediate region. The
plasmon-exciton coupling can be achieved and utilized as a sensor for sensing the refractive
index changes. Variation of geometrical parameters of the multilayer nanoshell affects the
strength of coupling and hence the sensitivity and detection accuracy of the sensor. The
understanding of coupling mechanisms paves the way for the optimal design of the proposed
sensor. We finally quantify and compare the performance of the sensor against previously
introduced similar sensors.
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