Fig. 1. Three-dimensional diagrams for the total electric field (red line), gating field (black line) and driving field (green line) in polarization gating pulse as a function of time: (a) Orthogonal polarization field; (b) double optical gating field. The change of laser intensity in x-polarized direction with time: (c) Orthogonal polarization field; (d) double optical gating field. (a)驱动脉冲电场中未加二次谐波场、(b)加入二次谐波场情况下, 偏振控制脉冲总电场(红色曲线)、控制(绿色曲线)及驱动脉冲电场(黑色曲线)随时间变化三维图; (c)未加入二次谐波场、(d)加入二次谐波场情况下, 驱动脉冲电场光强随时间变化曲线图

Fig. 2. High order harmonic generation from helium atom irradiated by the polarization gating pulse with 4 fs pulse width. Red line corresponds to the double optical gating scheme; black line corresponds to the orthogonal polarization gating scheme.脉宽为4 fs的偏振控制脉冲激光与氦原子相互作用得到的高次谐波发射谱, 其中红线对应于双光学控制方案, 黑线对应于正交偏振控制方案

Fig. 3. Variations of the amplitude of x-polarized (black curve) and y-polarized field (red curve), and the ionization rate of the helium atom (filled blue region) with time: (a) Double optical gating scheme; (b) orthogonal polarization gating scheme. Evolution of the harmonics with ionization (black) and recombination (red) time in the x polarized field case: (c) Double optical gating scheme; (d) orthogonal polarization gating scheme. (a)双光学控制方案、(b)正交偏振控制方案下, x方向驱动脉冲电场(黑色)、y方向控制脉冲电场(红色)及氦原子电离速率(蓝色填充区域)随时间的变化; (c)双光学控制方案、(d)正交偏振控制方案下, 高次谐波次数随电离(黑色点线)和复合时刻(红色点线)的变化

Fig. 4. In the case of double optical gating scheme, driving pulse field (red line), the ionization rate of helium atom (filled blue region) and the closest distance of electron to nucleus (green line) as a function of time.双光学控制方案中, 驱动脉冲电场(红色曲线)、氦原子的电离率(蓝色填充区域)、电离概率(黑色曲线)和电子回核最近距离(绿色曲线)随时间的变化

Fig. 5. Time-frequency analysis of harmonic emission in double optical gating scheme.双光学控制方案中谐波发射的时频分析图像

Fig. 6. Attosecond pulse generation from (a) double optical gating scheme and (b) orthogonal polarization gating scheme.阿秒脉冲产生时域图　(a)双光学控制方案; (b)正交偏振控制方案.