title: Localized multiphoton emission of femtosecond electron pulses from metal nanotips.
abstract: Intense multiphoton electron emission is observed from sharp (approximately 20 nm radius) metallic tips illuminated with weak 100-pJ, 7-fs light pulses. Local field enhancement, evidenced by concurrent nonlinear light generation, confines the emission to the tip apex. Electrons are emitted from a highly excited nonequilibrium carrier distribution, resulting in a marked change of the absolute electron flux and its dependence on optical power with the tip bias voltage. The strong optical nonlinearity of the electron emission allows us to image the local optical field near a metallic nanostructure with a spatial resolution of a few tens of nanometers in a novel tip-enhanced electron emission microscope.
authors.affiliation: Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Ropers
authors.forename: D R
authors.initials: DR
authors.lastname: Solli
authors.forename: C P
authors.initials: CP
authors.lastname: Schulz
authors.forename: C
authors.initials: C
authors.lastname: Lienau
authors.forename: T
authors.initials: T
authors.lastname: Elsaesser