Controlling multipolar surface plasmon excitation through the azimuthal phase structure of electron vortex beams

Autor(es)

Ugarte, Daniel ; Ducati, Caterina

• Tipo de documento: Artigo Científico
• Fonte: PHYSICAL REVIEW B; v. 93, n. 20, p. 9-pg., 2016-05-11.

Resumo

We have theoretically studied how the azimuthal phase structure of an electron vortex beam excites surface plasmons on metal particles of different geometries as observed in electron energy loss spectroscopy (EELS). We have developed a semiclassical approximation combining a ring-shaped beam and the dielectric formalism. Our results indicate that for the case of total orbital angular momentum transfer, we can manipulate surface plasmon multipole excitation and even attain an enhancement factor of several orders of magnitude. Since electron vortex beams interact with particles mostly through effects due to azimuthal symmetry, i.e., in the plane perpendicular to the electron beam, anisotropy information (longitudinal and transversal) of the sample may be derived in EELS studies by comparing nonvortex and vortex beam measurements. (AU)

• Processo FAPESP: 14/01045-0 - Estudo por técnicas avançadas de microscopia eletrônica de agregados metálicos e materiais nanocompósitos utilizados em aplicações fotovoltaicas
• Beneficiário: Daniel Mario Ugarte
• Modalidade de apoio: Bolsas no Exterior - Pesquisa