Fano Resonance in Ion-Bombarded Au-SiO2 Nanocomposites: Analysis of Mode Coupling and Optical Properties

This study investigates the optical properties of ion-bombarded Au-SiO2 nanocomposites, focusing on the enhanced Fano resonance observed in these samples. The formation of nanocrystals and nanocavities due to ion bombardment leads to significant interactions between plasmonic and vibrational modes, resulting in pronounced Fano resonance in the strong coupling regime. The study aims to explain the closer spacing of modes, the elevated baseline absorbance, and the asymmetric lineshape observed in the ion-bombarded samples. A detailed analysis is provided, comparing these findings with other sample preparations, such as Au-coated SiO2 and 20 nm Au colloidal on SiO2. The implications of these results for understanding plasmonic behavior and their potential applications in nanophotonics are discussed.