KrF激光脉冲整形研究

 实验研究了脉冲堆积法对KrF激光的整形能力。利用受激布里渊散射(SBS)压缩脉冲获得了脉宽为3~5 ns的短脉冲，用4束激光堆积获得了脉宽为10~15 ns、平顶宽度为5~10 ns的整形脉冲。利用实测SBS脉冲数据，对脉冲堆积法进行了数值模拟，模拟的脉冲宽度为12.7 ns，平顶宽度为7.7 ns，该结果与实验相符。对脉冲堆积法的任意整形能力进行了模拟，讨论了脉冲宽度变化对整形的影响，发现脉宽变化在5%以内时，对整形脉冲的影响较小。对整形脉冲的放大进行了定性研究，结果表明：平顶脉冲通过放大器后，前沿部分放大较多，由于饱和作用，后沿放大较少；如果前端整形脉冲前沿为斜坡状，放大后可以得到近平顶的脉冲。

KrF laser pulse shaping by pulse stacking

Pulse shaping of KrF laser by pulse stacking was experimentally studied.Compressed pulses by stimulated Brillouin scattering,short pulses with pulse-widths of 3~5 ns were gained.Shaped pulses with pulse-widths of 10~15 ns,flat-top-widths of 5~10 ns were obtained under four laser beams stacking.Using these experimental data,pulse stacking was numerically simulated,and similar results(pulse-widths of 12.7 ns,flat-top-widths of 7.7 ns) with experiment were acquired.Ability of arbitrary pulse shaping was numerically studied,and the influence of various pulse widths on shaped pulse was discussed.When variation of pulse width was less than 5%,it had little influence on shaped pulse.The amplification of the shaped pulse was theoretically and qualitatively analyzed.The results show that the front edge of the flat-top pulse is more amplified than the back edge after it goes through the amplifier because of influence of saturation.If the front edge of the front-end shaped pulse is sloping,the approximately flat-top pulse after amplified can be obtained.