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 HHG spectrum produced from the H2+ (D2+) molecule in the trapezoidal laser pulse and the H2+ (D2+) molecule in the combined laser pulse. The intensities of harmonics for the H2+ (D2+) molecule in the combined laser pulse are shifted down by 2 orders (4 orders) for clarity. The harmonic orders between the 1st and 33rd, 35th and 65th, and 67th and 97th are separately shown in Fig. 2(a), Fig. 2(b), and Fig. 2(c) for a better visualization.