Heidelberg 2015 – scientific programme
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A: Fachverband Atomphysik
A 24: Attosecond physics
A 24.5: Talk
Wednesday, March 25, 2015, 15:30–15:45, C/kHS
Time Delays in Two-Photon Ionization — Jing Su1, •Hongcheng Ni1,2, Agnieszka Jaron-Becker1, and Andreas Becker1 — 1JILA and Department of Physics, University of Colorado, Boulder, Colorado 80309-0440, USA — 2Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straße 38, 01187 Dresden, Germany
We study the time delays in two-photon ionization of the helium atom. We find that in the case of a nonresonant transition the absorption of the two photons occurs without time delay. In contrast, for a resonant transition a substantial absorption time delay is present, which scales linearly with the duration of the ionizing pulse. The two-photon absorption time delay can be related to the phase acquired during the transition of the electron from the initial ground state to the continuum.