Spectral redshift of high-order harmonics by adding a weak pulse in the falling part of the trapezoidal laser pulse
Pan Xue-Fei, Zhang Jun, Ben Shuai, Xu Tong-Tong, Liu Xue-Shen †
       

(color online) The time-frequency distribution of the HHG spectra from (a) H2+ molecule driven by the trapezoidal laser pulse, (b) H2+ molecule driven by the combined laser pulse, and (c) D2+ molecule driven by the combined laser pulse.