Fig. 3: Simulated XUV pulses as a function of the gas pressure.
From: Isolated attosecond pulse generation in a semi-infinite gas cell driven by time-gated phase matching

a Simulation results of the XUV spectrum as a function of the gas pressure. b On-axis IAP obtained at pressure values of 2 mbar (blue), 6 mbar (green), 10 mbar (orange), and 14 mbar (dark red) after performing the Fourier transform of a sub-set of the HHG spectra indicated by dotted lines in (a)