title: High-resolution imaging and spectroscopy of multipolar plasmonic resonances in aluminum nanoantennas.
abstract: We report on the high resolution imaging of multipolar plasmonic resonances in aluminum nanoantennas using electron energy loss spectroscopy (EELS). Plasmonic resonances ranging from near-infrared to ultraviolet (UV) are measured. The spatial distributions of the multipolar resonant modes are mapped and their energy dispersion is retrieved. The losses in the aluminum antennas are studied through the full width at half-maximum of the resonances, unveiling the weight of both interband and radiative damping mechanisms of the different multipolar resonances. In the blue-UV spectral range, high order resonant modes present a quality factor up to 8, two times higher than low order resonant modes at the same energy. This study demonstrates that near-infrared to ultraviolet tunable multipolar plasmonic resonances in aluminum nanoantennas with relatively high quality factors can be engineered. Aluminum nanoantennas are thus an appealing alternative to gold or silver ones in the visible and can be efficiently used for UV plasmonics.
authors.affiliation: Institut Charles Delaunay - Laboratoire de nanotechnologies et d'instrumentation optique, UMR CNRS 6281, Université de Technologie de Troyes , Troyes 10010, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Martin
authors.forename: Mathieu
authors.initials: M
authors.lastname: Kociak
authors.forename: Zackaria
authors.initials: Z
authors.lastname: Mahfoud
authors.forename: Julien
authors.initials: J
authors.lastname: Proust
authors.forename: Davy
authors.initials: D
authors.lastname: Gérard
authors.forename: Jérôme
authors.initials: J
authors.lastname: Plain
keywords: Aluminum; Electron Energy Loss Spectroscopy; Losses; Multipoles; Plasmonics; Q Factor