Photoemission electron microscopy of localized surface plasmons in silver nanostructures at telecommunication wavelengths

We image the field enhancement at Ag nanostructures using femtosecond laser pulses with a center wavelength of 1.55 micrometer. Imaging is based on non-linear photoemission observed in a photoemission electron microscope (PEEM). The images are directly compared to ultra violet PEEM and scanning electron microscopy (SEM) imaging of the same structures. Further, we have carried out atomic scale scanning tunneling microscopy (STM) on the same type of Ag nanostructures and on the Au substrate. Measuring the photoelectron spectrum from individual Ag particles shows a larger contribution from higher order photoemission process above the work function threshold than would be predicted by a fully perturbative model, consistent with recent results using shorter wavelengths. Investigating a wide selection of both Ag nanoparticles and nanowires, field enhancement is observed from 30% of the Ag nanoparticles and from none of the nanowires. No laser-induced damage is observed of the nanostructures neither during the PEEM experiments nor in subsequent SEM analysis. By direct comparison of SEM and PEEM images of the same nanostructures, we can conclude that the field enhancement is independent of the average nanostructure size and shape. Instead, we propose that the variations in observed field enhancement could originate from the wedge interface between the substrate and particles electrically connected to the substrate

Research Institutes in the ERA: WP2 2007/S 106-12999 FORESIGHT-200702 Lot 2 WP3

This is the final report of a study looking at the past and potential future of research institutes in Europe. In contrast to the universities, which are widely studied, the institutes are barely part of the EU policy discussion and the discussion about the European Research Area. The study therefore focuses on institutes in six fields, aiming to provide a broad spread of analysis that can improve understanding of the institutes and underpin policymaking in the institute sector. The overall aim of the study is to provide a basis for informing EU- and national-level policies about the role of research institutes in the development of the European Research Area (ERA). If the ERA is to become a reality, then aspects of Europe’s institute system will need to be tuned towards effectiveness and efficiency at the European level and not only, as at present, the national level. We therefore place particular emphasis on issues related to internationalisation and the international division of labour