title: Probing of optical near-fields by electron Rescattering on the 1 nm scale.
abstract: We present a new method of measuring optical near-fields within ~1 nm of a metal surface based on rescattering of photoemitted electrons. With this method, we precisely measure the field enhancement factor for tungsten and gold nanotips as a function of tip radius. The agreement with Maxwell simulations is very good. Further simulations yield a field enhancement map for all materials, which shows that optical near-fields at nanotips are governed by a geometric effect under most conditions, while plasmon resonances play only a minor role. Last, we consider the implications of our results on quantum mechanical effects near the surface of nanostructures and discuss features of quantum plasmonics.
authors.affiliation: Max-Planck-Institut für Quantenoptik , 85748 Garching bei München, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Thomas
authors.forename: Michael
authors.initials: M
authors.lastname: Krüger
authors.forename: Michael
authors.initials: M
authors.lastname: Förster
authors.forename: Markus
authors.initials: M
authors.lastname: Schenk
authors.forename: Peter
authors.initials: P
authors.lastname: Hommelhoff
mesh_terms: D004583:Electrons; D006046:Gold / Q000737:chemistry; D008027:Light; D008670:Metals / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D020349:Surface Plasmon Resonance
chemical_list: D008670:Metals; D006046:Gold