naa a22 4500 510817742 CHVBK 20180411083516.0 cr unu---uuuuu 180411e20130601xx s 000 0 eng 10.1007/s11468-012-9470-1 doi (NATIONALLICENCE)springer-10.1007/s11468-012-9470-1 Electron Energy Loss and One- and Two-Photon Excited SERS Probing of "Hot” Plasmonic Silver Nanoaggregates [Elektronische Daten] [Shima Kadkhodazadeh, Jakob Wagner, Virginia Joseph, Janina Kneipp, Harald Kneipp, Katrin Kneipp] We report electron energy loss spectroscopy (EELS) and one- and two-photon excited surface-enhanced Raman scattering (SERS) and hyper Raman studies on plasmonic silver nanoaggregates. By comparison with computations, EELS imaging reveals an inverse relationship between local field intensity in an optical experiment and electron energy loss intensity at energies corresponding to excitation wavelengths used for optical probing. This inverse relation exists independent on specific nanoaggregate geometries and is mainly controlled by the gap size between the particles forming the aggregate. The ratio between two- and one-photon excited SERS measured at different excitation wavelengths provides information about local fields in the hottest spots and their dependence on the photon energy. Our data verify experimentally the predicted increase of local optical fields in the hot spots with increasing wave lengths. The reported findings show new experimental ways to characterize local fields of plasmonic nanostructures. This is of particular importance for complex structures which are not easily approachable by computations. Springer Science+Business Media New York, 2012 Surface-enhanced Raman scattering (SERS) nationallicence Electron energy loss spectroscopy (EELS) nationallicence Plasmonic nanoatructures nationallicence Silver nanoaggregates nationallicence Plasmonic dimers nationallicence Two-photon excitation nationallicence Kadkhodazadeh Shima Center for Electron Nanoscopy, Technical University Denmark, 2800, Kgs. Lyngby, Denmark aut Wagner Jakob Center for Electron Nanoscopy, Technical University Denmark, 2800, Kgs. Lyngby, Denmark aut Joseph Virginia Department of Chemistry, Humboldt University Berlin, 12489, Berlin, Germany aut Kneipp Janina Department of Chemistry, Humboldt University Berlin, 12489, Berlin, Germany aut Kneipp Harald Department of Physics, Technical University Denmark, Fysikvej 309, 2800, Kgs. Lyngby, Denmark aut Kneipp Katrin Department of Physics, Technical University Denmark, Fysikvej 309, 2800, Kgs. Lyngby, Denmark aut Plasmonics Springer US; http://www.springer-ny.com 8/2(2013-06-01), 763-767 1557-1955 8:2<763 2013 8 11468 https://doi.org/10.1007/s11468-012-9470-1 text/html Onlinezugriff via DOI 1 brief-communication jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11468-012-9470-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kadkhodazadeh Shima Center for Electron Nanoscopy, Technical University Denmark, 2800, Kgs. Lyngby, Denmark aut NATIONALLICENCE 700 1- Wagner Jakob Center for Electron Nanoscopy, Technical University Denmark, 2800, Kgs. Lyngby, Denmark aut NATIONALLICENCE 700 1- Joseph Virginia Department of Chemistry, Humboldt University Berlin, 12489, Berlin, Germany aut NATIONALLICENCE 700 1- Kneipp Janina Department of Chemistry, Humboldt University Berlin, 12489, Berlin, Germany aut NATIONALLICENCE 700 1- Kneipp Harald Department of Physics, Technical University Denmark, Fysikvej 309, 2800, Kgs. Lyngby, Denmark aut NATIONALLICENCE 700 1- Kneipp Katrin Department of Physics, Technical University Denmark, Fysikvej 309, 2800, Kgs. Lyngby, Denmark aut NATIONALLICENCE 773 0- Plasmonics Springer US; http://www.springer-ny.com 8/2(2013-06-01), 763-767 1557-1955 8:2<763 2013 8 11468 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer