A quantum mechanical study of optical excitations in nanodisk plasmonic oligomers

Using state-of-the-art quantum-mechanical calculations, we investigate the optical excitations in plasmonic nanodisk oligomers. We show that different tuning parameters such as the constitution (size and intrinsic optical properties of individual nanodisks), configuration (number of satellite nanodisks), and the spatial arrangement of satellite nanodisks critically influence the optical features of nanodisk oligomers. Our theoretical results demonstrate significantly enhanced absorption in nanodisk oligomers in comparison to individual nanodisks and, additionally, vivid optical modulations due to the creation of nanodisk oligomer homotops. Transition density maps corresponding to the main peaks in the absorption spectra provided new insight into the nature of the optical excitations. The insights gained from this theoretical study will be useful in the design of novel plasmonic nanodisk oligomers.