【作者】 李琨； 张彬； 朱启华； 黄小军；

【Author】 LI Kun~1 ZHANG Bin~1 ZHU Qi-hua~2 HUANG Xiao-jun~2 ~1School of Electronic Information.Sichuan University,Chengdu.Sicuan 610064.China ~2Research Center of Laver Fusio,China Academy of Engineering Physics.Mianyang.Sichuan 621900.China

【机构】 四川大学电子信息学院； 中国工程物理研究院激光聚变研究中心；

【摘要】 针对高强度飞秒脉冲,详细讨论了采用 KDP 晶体的Ⅰ类及Ⅱ类二倍频过程中提高二倍频转换效率的方法。研究结果表明,群速度失配会导致二倍频光脉冲宽度的增大和转换效率的降低,非线性相位调制使二倍频光脉冲形状发生畸变,降低转换效率。针对Ⅰ类二倍频,采用适当的初始空间相位失配,对由自相位调制及交叉相位调制引起的转换效率的下降有一定的补偿作用；针对Ⅱ类二倍频,对入射基频 e 光采取适当的时间预延迟,可有效增大转换效率并抑制二倍频光脉冲的展宽。更多还原

【Abstract】 The methods for increasing the conversion efficiency of the type Ⅰ and type Ⅱ second harmonic generation with KDP crystal for the ultra intense femtosecond laser pulse have been discussed in detail.The results show that group-velocity mismatching is the main reason of the broadening of the second harmonic pulse and could lead to the decrement of conversion efficiency.The effects of nonlinear phase-modulation cause the distortion of the shape of the second harmonic pulse and also decrease the conversion efficiency.For the type [second harmonic generation,the proper spatial phase-mismatching can be helpful in compensation for the decrement of the conversion efficiency caused by the self-and cross-phase-modulation.For the type [1 second harmonic generation, the proper time predelay to the incident fundamental extraordinary pulse can efficiently increase the conversion efficiency,and also restrain the broadening of second harmonic pulse.更多还原