Ultrafast Optical Excitations in Metal-Semiconductor Hybrid Nanostructures : A Route to Active Plasmonics

Future nano-plasmonic devices will most likely rely on the interplay between the strong intrinsic optical nonlinearities of excitonic nanostructures and the ability of metallic nano-objects to concentrate electromagnetic fields locally. Consequently, the optical properties of hybrid nanostructures comprising active materials, e.g., semiconductors or J-aggregated molecules, and metals are currently attracting considerable attention. In favorable geometries, their properties are governed by a new class of short-lived quasiparticles, exciton - surface plasmon polaritons, in short "excimons" with hitherto unexplored nonequilibrium dynamics. Since the polariton dynamics in hybrid nanostructures occurs on very short timescale, ultrafast spectroscopy is an essential tool for the investigation of their properties. 

In this talk, the optical properties of prototypical hybrid nanostructures probed using ultrafast spectroscopy will be discussed. These hybrid structures are progressively becoming important for developing high efficiency optical devices.