Kiriyama Hiromitsu, Miyasaka Yasuhiro, Sagisaka Akito, Ogura Koichi, Nishiuchi Mamiko, Pirozhkov Alexander S, Fukuda Yuji, Kando Masaki, Kondo Kiminori
Opt Lett. 2020 Mar 1;45(5):1100-1103. doi: 10.1364/OL.384759.
We experimentally explore the generation of pre-pulses by post-pulses, created through internal reflection in the optical components, by the nonlinear process associated with the B-integral in the laser chain of the petawatt (PW) facility J-KAREN-P. At a large time delay between the main and the post-pulses, we have found that the pre-pulses are not generated from their counterpart post-pulses at an identical time difference before the main pulse, and the temporal shapes of the pre-pulses are greatly distorted asymmetrically. We have also observed that the peak intensities of the pre-pulses are drastically suppressed compared to the expected value at a small time delay. We briefly describe the origins of the pre-pulses generated by the post-pulses and demonstrate the removal of the pre-pulses by switching to optical components with a small wedge angle at our PW laser facility.
我们通过实验研究了在拍瓦（PW）装置J-KAREN-P的激光链中，由光学元件内部反射产生的后脉冲所引发的预脉冲的产生情况。该过程与B积分相关的非线性过程有关。在主脉冲和后脉冲之间存在较大时间延迟时，我们发现预脉冲并非在主脉冲之前相同的时间差从其对应的后脉冲产生，并且预脉冲的时间形状严重不对称地扭曲。我们还观察到，在较小时间延迟下，预脉冲的峰值强度与预期值相比大幅降低。我们简要描述了后脉冲产生预脉冲的起源，并展示了在我们的拍瓦激光装置中通过切换到具有小楔角的光学元件来消除预脉冲的方法。
