Analysis of phase dependence of the two single-attosecond-pulse generation techniques

For the sake of understanding the carrier-envelope-phase dependence of the two single-attosecond-pulse generation techniques,i.e.,amplitude gating and polarization gating,the influence of carrier-envelope phase of the driving field on the generation of extreme ultraviolet single attosecond pulse with either of the basic techniques was analyzed based on its principle and the three-step scenario of high-harmonic generation.It indicates that the optimal carrier-envelope phases for amplitude gating and polarization gating are 0 and 0.5π respectively,whose difference was induced by the close dependence of high-harmonic generation on the polarization feature of driving field.The results are of great significance to the generation and its related applications of extreme ultraviolet attosecond pulses with narrow pulse duration.