For investigations on laser wakefield electron acceleration, there is a strong demand for driving laser exhibiting high stability and good spatial-temporal quality. Here we present an upgraded 200TW/1Hz Ti:sapphire laser with following key characteristics. The fluctuation of pulse energy and beam pointing for consecutive 5400 pulses in 90 min are as low as 0.55% and 1.5μrad respectively. The compressed pulse duration is 23.7 fs, which is about 1.1 times of the Fourier-transform limit. The focal spot obtained by an f/30 off-axis parabolic mirror is 54 μm × 52 μm at 1/e², which is very close to the diffraction limit. Moreover, in the laser wakefield electron acceleration experiments driven by this upgraded 200TW/1Hz laser, quasi-mono-energetic electron beams are reproduced in consecutive shots. For successive 300 shots, the average peak energy of produced electron beams is 667 MeV, and the peak energy fluctuation is only 3.4%. The progresses on both driving laser and laser wakefield electron acceleration make the realization of compact X-ray free electron laser possible.

为了研究激光尾场电子加速度，强烈需要驱动显示出高稳定性和良好时空质量的激光器。在这里，我们展示了具有以下关键特性的升级版200TW / 1Hz Ti：蓝宝石激光器。90分钟内连续5400个脉冲的脉冲能量和光束指向的波动分别低至0.55％和1.5μrad。压缩后的脉冲持续时间为23.7 fs，约为傅里叶变换极限的1.1倍。f / 30离轴抛物面反射镜在1 / e ²处获得的焦点为54μm×52μm，非常接近衍射极限。此外，在由这种升级的200TW / 1Hz激光器驱动的激光尾场电子加速实验中，准单能电子束在连续发射中得以再现。对于连续300次发射，产生的电子束的平均峰值能量为667 MeV，峰值能量波动仅为3.4％。驱动激光器和激光尾场电子加速的进步使得紧凑的X射线自由电子激光器的实现成为可能。