Nanospectroscopy of metallic nanoparticles: Parametric study and technique comparative
Résumé
A localized surface plasmon resonance (LSPR) generated by an interaction of light and a metallic nanoparticle (NP) opens a wide horizon of studies in the different fields such as biosensing, health-care, tumor treatment, etc.. Nevertheless, the LSPR is very sensitive to interaction conditions: material, environment, geometry, polarization or angle of incidence.This investigation aims to fulfill a numerical and an experimental comparative study of the various size nanonparticles' LSPR evolution using different light sources and illumination types. The simulations are done with help of a commercial software from Lumerical Solutions Inc. based on the FDTD method. We verify the LSPR shifts caused by the well-known variations (size, geometry, environment changes). As a point source is used a vertical dipole placed in the vicinity of Ag NP. One may observe that there is LSPR shift for different distances between the source and NP. Moreover, the LSPR for dipole source varies from planewave illumination LSPR. We further find that there is LSPR shift for an horizontal dipole as well. The LSPR shift is quite intuitive for a dipole source depending on the distance between itself and NP, as we have coupled system. We demonstrate the electric field maps comparison of differently oriented dipoles and plane wave, which also can show the nature of the LSPR shift. At the current stage, our work shows promising results. For future we will do comparative studies via experiments and make the agreement with numerical simulations.