ausblenden:
Schlagwörter:
-
Zusammenfassung:
In this work, the absorption
spectra of an extreme ultraviolet (XUV) attosecond light pulse in argon
and molecular nitrogen are investigated as a function of a time delay between
the XUV pulse and a near-infrared (NIR) femtosecond light pulse and the NIR
peak intensity. The XUV pulses are produced by high-harmonic generation of
the NIR pulse yielding attosecond time resolution for the time-delay-dependent
absorption spectra. In this all-optical approach, the electronic and vibrational
quantum states of the target systems are excited by the weak XUV pulse and
dressed by the strong NIR pulse. The strong-field effects, which are observed
in the time- and intensity-dependent optical density, are compared between
argon and nitrogen. These are line-broadening, line-shape changes, sub-cycle
and slower modulations. Emphasis is placed on to the modulations, which
originate from two-NIR-photon transitions between different excited states.
Furthermore, a focus lies on the intensity-dependent line-shape changes of
both species. A measure for these changes is the laser-imposed phase of a
wave packet’s dipole moment, which is excited by the XUV pulse. This phase
is introduced in a dipole-control model and investigated for both species.
