Nanoparticle Electromagnetic Properties for Sensing Applications

Nanoparticles play a crucial role in biomedical and sensing applications. In this paper the design of non-spherical gold nanoparticles, operating in the near infrared and visible regime, is proposed. The structures consist of metallic resonating inclusions of different shapes embedded in a dielectric environment. Different geometries, such as cube, elliptical cylinder and rod are considered. The main purpose of this study is to develop new analytical formulas useful in the nanoparticle design for specific biomedical and sensing applications. These analytical models are developed in order to describe the electromagnetic behavior of the nanoparticles in terms of resonant wavelength position, magnitude and amplitude width for absorption and scattering cross section. The obtained results are compared to the numerical ones, performed by full-wave simulations, and to the experimental values existing in literature. A good agreement among analytical, experimental and numerical results was obtained. Then, the structure is analyzed in terms of sensitivity properties. Exploiting the proposed analytical models, it is possible to design the nanostructures with the desired electromagnetic properties. The results show that these structures can be successfully applied for sensing applications.