Fig. 2: Dependency of HHG spectra on RP and CEP in argon.
From: Strong-field coherent control of isolated attosecond pulse generation
The HHG process is driven in argon by the synthesized pulses and the XUV spectra are recorded with a grating XUV spectrometer. Depending on the spectral range, the spectra are dispersed by either a grating with 300 groove/mm (low photon energy) (a, c, d, g, h) or with 1200 groove/mm (high photon energy) (b, e, f, i, j). With the CEP fixed, XUV-spectra vary significantly with changing RP (a, b), where negative relative phase means the IR pulse arrives first. A CEP shift by π/2 completely changes the XUV spectra (c, e). On the other hand, XUV-spectra vary with CEP and the landscape of the CEP-dependent variation appears different when the RP is fixed at another value. (d, f, g, i and h, j) correspond to the XUV spectrum CEP-dependent variation with the RP fixed at 13.5 rad, 0.1 rad and −16.4 rad, marked with dashed line in (a, b), respectively. The integration time for each spectrum is 200 ms and a thin metallic filter is applied to block the driving laser beam (500 nm thick beryllium).
