title: Electron energy-loss spectroscopy (EELS) of surface plasmons in single silver nanoparticles and dimers: influence of beam damage and mapping of dark modes.
abstract: We demonstrate the use of a scanning transmission electron microscope (STEM) equipped with a monochromator and an electron energy loss (EEL) spectrometer as a powerful tool to study localized surface plasmons in metallic nanoparticles. We find that plasmon modes can be influenced by changes in nanostructure geometry and electron beam damage and show that it is possible to delineate the two effects through optimization of specimen preparation techniques and acquisition parameters. The results from the experimental mapping of bright and dark plasmon energies are in excellent agreement with the results from theoretical modeling.
authors.affiliation: Department of Materials, Imperial College London, London SW7 2AZ, United Kingdom. a.koh@imperial.ac.uk
authors.forename: Ai Leen
authors.initials: AL
authors.lastname: Koh
authors.forename: Kui
authors.initials: K
authors.lastname: Bao
authors.forename: Imran
authors.initials: I
authors.lastname: Khan
authors.forename: W Ewen
authors.initials: WE
authors.lastname: Smith
authors.forename: Gerald
authors.initials: G
authors.lastname: Kothleitner
authors.forename: Peter
authors.initials: P
authors.lastname: Nordlander
authors.forename: Stefan A
authors.initials: SA
authors.lastname: Maier
authors.forename: David W
authors.initials: DW
authors.lastname: McComb