Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 33: Nanostructures at Surfaces III

O 33.6: Vortrag

Dienstag, 12. März 2013, 11:45–12:00, H45

Emission cone narrowing of electrons in the strong field around a sharp metallic nanotip — Doojae Park, Björn Piglosiewicz, Slawa Schmidt, •Petra Groß, and Christoph Lienau — Ultraschnelle Nano-Optik, Institut für Physik, Universität Oldenburg, 26111 Oldenburg

When sharp, nanometer-sized metal tips are irradiated with few-cycle near-infrared laser pulses with around 1.6 µm center wavelength and few nJ energy, the strong laser field around the tip apex enables tunneling of electrons out of the tip. At these conditions, we find a pronounced strong-field acceleration of the electrons within the field gradient near the tip apex, and we observe a distinct narrowing of the emission cone angle of the fastest electrons.

We investigate the electron motion in the strong field around the nanostructure by recording angle-resolved kinetic energy spectra and using numerical simulations incorporating the curved, vectorial gradient of the oscillating laser field [1]. These studies show that the emission cone narrowing of the fastest electrons can be ascribed to the field-induced steering of sub-cycle electrons, which escape the tip’s near field within half an oscillation of the laser pulse. Our results indicate new possibilities for designing directional ultrafast electron sources.

[1] D. J. Park et al., Phys. Rev. Lett., in press (2012)