Effect of multipole excitations in electron energy-loss spectroscopy of surface plasmon modes in silver nanowires

Journal Article · Sun Dec 14 00:00:00 EST 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4903535· OSTI ID:22402754

Zhou, Xiuli; Norris, Theodore B. ^[1]; Hörl, Anton; Trügler, Andreas; Hohenester, Ulrich ^[2]

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1. Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States)
2. Institut für Physk, Karl-Franzens-Universität Graz, 8010 Graz (Austria)

We have characterized the surface plasmon resonance (SPR) in silver nanowires using spatially resolved electron energy loss spectroscopy (EELS) in the scanning transmission electron microscope. Non-symmetric EELS spectra due to high-k SPR propagation along the nanowire and spectral shifts due to higher-order mode excitation are observed when the beam is positioned near the tip of the nanowire. When the beam is far from the tip region and on the side of nanowire, no spectral shifts are observed as the beam is scanned in the radial direction of the nanowire. The experimental spectra are compared with three different theoretical approaches: direct numerical calculation of the energy loss, analytical models for energy loss, and numerical simulations using an optical model. All three models reproduce the spectral shifts as the electron beam approaches the cap of the nanowire. The analytical model reveals the origin of the shifts in high-order plasmon mode excitation.

• OSTI ID: 22402754
• Journal Information: Journal of Applied Physics, Vol. 116, Issue 22; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COMPUTERIZED SIMULATION
ELECTRON BEAMS
ELECTRONS
ENERGY LOSSES
ENERGY-LOSS SPECTROSCOPY
EXCITATION
QUANTUM WIRES
SILVER
SPECTRAL SHIFT
SURFACES
TRANSMISSION ELECTRON MICROSCOPY