Spectrally and Spatially Resolved Smith-Purcell Radiation in Plasmonic Crystals with Short-Range Disorder

Electrons interacting with plasmonic structures can give rise to resonant excitations in localized plasmonic cavities and to collective excitations in periodic structures. We investigate the presence of resonant features and disorder in the conventional Smith-Purcell effect (electrons interacting with periodic structures) and observe the simultaneous excitation of both the plasmonic resonances and the collective excitations. For this purpose, we introduce a new scanning-electron-microscope-based setup that allows us to probe and directly image new features of electron-photon interactions in nanophotonic structures like plasmonic crystals with strong disorder. Our work creates new possibilities for probing nanostructures with free electrons, with potential applications that include tunable sources of short-wavelength radiation and plasmonic-based particle accelerators.
United States. Army Research Office (Institute for Soldier Nanotechnologies. Contract W911NF-13-D-0001)
Israel Science Foundation (Grant 1310/13)
German-Israeli Project Cooperation
National Science Foundation (U.S.). Graduate Research Fellowship Program (Award 1122374)
National Science Foundation (U.S.). Materials Research Science and Engineering Centers (Program) (Award DMR-1419807)
Seventh Framework Programme (European Commission) (Grant 328853- MC-BSiCS)