Optical Properties of Modified Nanorod Particles for Biomedical Sensing

In this paper, an analytical and numerical investigation for modified gold nanorod particles, operating in the visible and in the infrared regime is proposed. The modified particles consist in a core/shell structure (dielectric core/metallic shell) embedded in a dielectric environment. Their electromagnetic properties, in terms of extinction cross section (absorption and scattering) for both longitudinal and transverse modes excitation, are evaluated. In particular, new analytical models are developed, describing their resonant behavior. Good agreement among the analytical, numerical, and experimental results was achieved. Exploiting the obtained models, the nanoparticle sensitivity was studied. Analytical and full wave results validate the high sensitivity performances and the potential role of such structures to be used for sensing applications.