Figure 7
From: Even harmonic generation in isotropic media of dissociating homonuclear molecules

HHG spectrum for a pulse of 800 nm, I = 3 × 1014 W/cm2 and 30 optical cycles for
and
.
The dashed vertical lines indicates odd harmonics. The thick vertical lines indicate the ionization threshold (left line) and the cut-off energy obtained from Ecutoff = Ip + 3.17Up (right line).