Hannover 2010 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 13: Ultrashort Laser Pulses: Generation II

Q 13.2: Talk

Monday, March 8, 2010, 16:45–17:00, F 342

Energy-resolved measurements of laser-triggered electron pulses from ultrasharp metal tips — •Markus Schenk, Michael Krüger, and Peter Hommelhoff — Max-Planck-Institut für Quantenoptik, Hans-Kopfermann-Straße 1, 85748 Garching bei München, Germany

For quantum optics experiments with free electrons a spatially and temporally well-controlled electron source is of high interest. Focusing few-cycle pulses of a Titanium:Sapphire-oscillator onto a sharp metal tip triggers electron emission on short timescales. Here we show that different processes occur and can be favored by properly choosing parameters such as laser intensity and static electric field[1]. We perform energy resolved measurements. At low static fields we observe pure over-the-barrier multi-photon photoemission. For higher static fields (narrower tunneling barrier) electrons from below the barrier can tunnel out of the tip after absorption of one or two photons (photo-field emission). At higher laser intensities electrons with energies corresponding to the absorption of up to 7 photons are observed (above-threshold-photoemission). This talk will give an overview about these observed processes.

[1] see also contributions by Michael Krüger et al. and Hanno Kaupp et al.