title: Time of flight-photoemission electron microscope for ultrahigh spatiotemporal probing of nanoplasmonic optical fields.
abstract: Nanoplasmonic excitations as generated by few-cycle laser pulses on metal nanostructures undergo ultrafast dynamics with timescales as short as a few hundred attoseconds (1 as = 10(-18) s). So far, the spatiotemporal dynamics of optical fields localized on the nanoscale (nanoplasmonic field) have been hidden from direct access in the real space and time domain. An approach which combines photoelectron emission microscopy and attosecond streaking spectroscopy and which provides direct and non-invasive access to the nanoplasmonic field with nanometer-scale spatial resolution and temporal resolution of the order of 100 as has been proposed (Stockman et al 2007 Nat. Photon. 1 539). To implement this approach, a time of flight-photoemission electron microscope (TOF-PEEM) with ∼25 nm spatial and ∼50 meV energy resolution, which has the potential to detect a nanoplasmonic field with nanometer spatial and attosecond temporal resolution, has been developed and characterized using a 400 nm/60 ps pulsed diode laser. The first experimental results obtained using this newly developed TOF-PEEM in a two-photon photoemission mode with a polycrystalline Cu sample and an Ag microstructure film show that the yield and the kinetic energy of the emitted photoelectrons are strongly affected by the nanolocalized plasmonic field.
authors.affiliation: Changchun University of Science and Technology, Changchun 130022, People's Republic of China. Fakultät für Physik, Ludwig-Maximilians-Universität München, Am Coulombwall 1, 85748 Garching, Germany.
authors.forename: Jingquan
authors.initials: J
authors.lastname: Lin
authors.forename: Nils
authors.initials: N
authors.lastname: Weber
authors.forename: Adrian
authors.initials: A
authors.lastname: Wirth
authors.forename: Soo Hoon
authors.initials: SH
authors.lastname: Chew
authors.forename: Matthias
authors.initials: M
authors.lastname: Escher
authors.forename: Michael
authors.initials: M
authors.lastname: Merkel
authors.forename: Matthias F
authors.initials: MF
authors.lastname: Kling
authors.forename: Mark I
authors.initials: MI
authors.lastname: Stockman
authors.forename: Ferenc
authors.initials: F
authors.lastname: Krausz
authors.forename: Ulf
authors.initials: U
authors.lastname: Kleineberg