Fig. 1. Schematic diagram of position of mirror in double-pass amplification.双程放大实验反射镜位置示意图

Fig. 2. The pulse waveform of single-pass amplification and double-pass amplification output: (a) Single-pass amplification output; (b) double-pass amplification output.单程放大和双程放大输出脉冲波形　(a)单程放大输出; (b)双程放大输出

Fig. 3. CCD image in capillary radius: (a) Intensity image of single-pass amplification; (b) intensity image of double-pass amplification.毛细管径向上CCD图像　(a)单程放大强度图像; (b)双程放大强度图像

Fig. 4. Laser divergence angle in capillary radius: (a) Divergence angle of the single-pass amplification; (b) divergence angle of the double-pass amplification.毛细管径向上激光束散角　(a) 单程放大的束散角; (b) 双程放大的束散角

Fig. 5. Gain coefficient as a function of time for 69.8 nm laser.69.8 nm激光的增益系数随时间的变化

Fig. 6. Gain coefficient as a function of angle in the spatial distribution for 69.8 nm laser peak.69.8 nm激光峰值处的增益系数在空间上的分布情况