Figure 8
Experimentally measured long (a) and short (b) trajectory intensities of H15–H37 as a function of pulse energy of the fundamental field. H17 is shown in gray, H21 in black, and H23 in brown, while the remaining harmonics are shown in a rainbow color scale from dark blue (H15) to dark red (H37) with increasing order. The dashed line indicates roughly the conditions of Fig. 1. The inset of (a) schematically shows how the Rydberg series for the 3s electrons in combination with the continuum for the 3p electrons creates a series of window resonances. Absorption of an XUV photon can create a coherent superposition of the two valence electrons which interfere and affects the absorption cross-section σabs42. In argon this amounts to a reduction of the absorption cross-section43. The vertical arrows within the inset indicate the expected direction of the light induced energy-shift of the respective 3s13p6np1 states.
