Berlin 2001 – wissenschaftliches Programm

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A: Atomphysik

A 5: Posters Tuesday (Photoionisation, Multi Photon Processes)

A 5.28: Poster

Dienstag, 3. April 2001, 12:30–15:00, AT3

Simultaneous investigation of the three most important effects of atoms in strong laser fields — •Felix Grasbon, Gerhard G. Paulus, and Herbert Walther — MPI für Quantenoptik, D-85748 Garching

Atoms interacting with intense laser fields show three distinctive phenomena: Above-threshold ionization (ATI), non-sequential double ionization (NSDI), and high-harmonic generation (HHG). Theoretical models show that all of them are governed by much the same physics. Similarities and differences can easily be detected by studying their yields as a function of the ellipticity of the laser polarization.

We present the first experiment that investigates ATI, NSDI, and HHG under identical conditions. The measurements were done with a femtosecond laser system with an extremely high repetition rate (100kHz). The photoelectrons and the ions are detected by time-of-flight spectroscopy and the harmonics in a XUV spectrometer with a novel CCD detector. The results are compared to a semi-classical model. They confirm the overall validity of that theory, however, we also observe deviations between theory and experiment.