Abstract
Fabrication and synthesis of plasmonic structures is rapidly moving towards sub-nanometer accuracy incontrol over shape and inter-particle distance. This holds the promise for developing device componentsbased on novel, non-classical electro-optical effects. Monochromated electron energy-loss spectroscopy(EELS) has in recent years demonstrated its value as a qualitative experimental technique in nano-optics andplasmonic due to its unprecedented spatial resolution. Here, we demonstrate that EELS can also be usedquantitatively, to probe surface plasmon kinetics and damping in single nanostructures. Using thisapproach, we present from a large (.50) series of individual gold nanoparticles the plasmon Quality factorsand the plasmon Dephasing times, as a function of energy/frequency. It is shown that the measured generaltrend applies to regular particle shapes (rods, spheres) as well as irregular shapes (dendritic, branchedmorphologies). The combination of direct sub-nanometer imaging with EELS-based plasmon dampinganalysis launches quantitative nanoplasmonics research into the sub-nanometer realm.