Polarimetric techniques for determining morphology and optical features of High Refractive Index dielectric nanoparticles size

Abstract

The spectral evolution of the degree of linear polarization (PL) at a scattering angle of 90º is studied numerically for high refractive index (HRI) dielectric spherical nanoparticles. The behaviour of PL(90º) is analyzed as a function of the refractive index of the surrounding medium and the particle radius. We focus on the spectral region where both electric and magnetic resonances of order not higher than two are located for various semiconductor materials with low absorption. The spectral behavior of PL(90º) has only a small, linear dependence on nanoparticle size R. This weak dependence makes it experimentally feasible to perform real-time retrievals of both the refractive index of the external medium and the NP size R. From an industrial point of view, pure materials are nonrealistic, since they can only be provided under certain conditions. For this reason, we also study the effect of contaminants on the resonances of silicon NPs by considering the spectral evolution of PL(90º).