Photoconductive control of high-order localized surface plasmon modes in Au-Si-Au nanodisk stacking

We perform full-wave electromagnetic simulations to investigate the formation of higher-order localized surface plasmons (LSP) in a multilayered Au-Si-Au nanodisk architecture and their evolution with the doping level and thickness of the semiconducting layer. We show that higher-order LSP modes can be efficiently excited and controlled not only by changing the thickness of the intermediate Si layer but also by optically tuning its doping level. We provide a detailed study of the nature and origin of the hybrid modes resulting from the hybridization of nanodisk primitive LSP modes. This approach substantially improves the functionality of the nanodisk stack structure and opens up a new practical pathway for the active control of the optical response of plasmonic-based and semiconducting-based devices.