(color online) HHG power spectra with (a) and (b) by varying the envelope delay τ_d. In each plot, the spectra with , , and are presented by black dash-dotted line, red dash line, and blue solid line, respectively. In panel (a), the CEP shift is tuned to for , 0.101645 for , and 0.101703 for for the achievement of multiphoton resonance. In panel (b), the CEP shift is tuned to for , 0.114277 for , and 0.114485 for for the achievement of multiphoton resonance. The other parameters are the same as those in Fig. 1.