Spectral Analysis of Gold Nanorods as Active Plasmonic Media in Different Dielectric Environments (Air and Water) across Visible and NIR Wavelengths

Abstract

     Gold nanorods (GNRs) have emerged as pivotal nanostructures in optical and electronic applications due to their unique localized surface plasmon resonance (LSPR) properties, which are highly sensitive to particle geometry and the surrounding medium. This study investigates the effects of spatial variations, radius of the cylindrical structure, surrounding media, and insulating layers on the scattering behavior of GNRs under illumination at selective wavelengths (610, 710, 810, 910) nm. Three key simulation models were developed: The first simulation model was on the impact of varying interparticle distances in different media (air and water), revealing significant shifts in scattering intensity and plasmonic spectra due to enhanced interactions at closer proximities. The second simulation model explored the role of insulating layers, demonstrating that coatings such as silica altered electric field distributions and attenuated environmental influences, resulting in modified scattering spectra. The third simulation model focused on the impact of varying the radius of GNRs in different media (air and water), again showing notable shifts in scattering intensity and plasmonic behavior. The results clearly highlight the critical role of gold nanoparticles as active nanostructures in controlling the optical response, particularly through the LSPR mechanism. This emphasizes their potential in nanophotonic applications, such as high-sensitivity optical sensors, nanoscale imaging systems, and optoelectronic devices. The findings also show that the maximum benefit of nanostructures in medical fields can be obtained by carefully designing these structures.