--- res: bibo_abstract: - Metal nanoparticles host localized plasmon excitations that allow the manipulation of optical fields at the nanoscale. Despite the availability of several techniques for imaging plasmons, direct access into the symmetries of these excitations remains elusive, thus hindering progress in the development of applications. Here, we present a combination of angle-, polarization-, and space-resolved cathodoluminescence spectroscopy methods to selectively access the symmetry and degeneracy of plasmonic states in lithographically fabricated gold nanoprisms. We experimentally reveal and spatially map degenerate states of multipole plasmon modes with nanometer spatial resolution and further provide recipes for resolving optically dark and out-of-plane modes. Full-wave simulations in conjunction with a simple tight-binding model explain the complex plasmon structure in these particles and reveal intriguing mode-symmetry phenomena. Our approach introduces systematics for a comprehensive symmetry characterization of plasmonic states in high-symmetry nanostructures.@eng bibo_authorlist: - foaf_Person: foaf_givenName: Viktor foaf_name: Myroshnychenko, Viktor foaf_surname: Myroshnychenko foaf_workInfoHomepage: http://www.librecat.org/personId=46371 - foaf_Person: foaf_givenName: Natsuki foaf_name: Nishio, Natsuki foaf_surname: Nishio - foaf_Person: foaf_givenName: F. Javier foaf_name: García de Abajo, F. Javier foaf_surname: García de Abajo - foaf_Person: foaf_givenName: Jens foaf_name: Förstner, Jens foaf_surname: Förstner foaf_workInfoHomepage: http://www.librecat.org/personId=158 orcid: 0000-0001-7059-9862 - foaf_Person: foaf_givenName: Naoki foaf_name: Yamamoto, Naoki foaf_surname: Yamamoto bibo_doi: 10.1021/acsnano.8b03926 bibo_issue: '8' bibo_volume: 12 dct_date: 2018^xs_gYear dct_isPartOf: - http://id.crossref.org/issn/1936-0851 - http://id.crossref.org/issn/1936-086X dct_language: eng dct_publisher: American Chemical Society (ACS)@ dct_subject: - tet_topic_plasmonics dct_title: Unveiling and Imaging Degenerate States in Plasmonic Nanoparticles with Nanometer Resolution@ ...