Yang Xihang, Tang Xiaofeng, Liu Yanqi, Bin Jianhui, Leng Yuxin
Opt Express. 2023 Sep 25;31(20):33753-33764. doi: 10.1364/OE.501490.
Post-compression can effectively further improve the peak power of laser pulses by shortening the pulse duration. Which has been investigated in various ranges of energy and central wavelength. However, the spatial intensity profile of high-peak-power laser pulses is generally inhomogeneous due to pump lasers, imperfect optical components, and dust in the optical layout. In post-compression, the B-integral is proportional to intensity, and wavefront distortions are induced in the spectral broadening stage, leading to a decrease in focusing intensity. Moreover, the beam intensity may be strongly modulated and beam inhomogeneity will be intensified in this process, causing damage to optical components and limiting the achievement of high peak power enhancement. In this study, to address these challenges, the laser pulse is first smoothed by introducing spatial dispersion using prism pairs or asymmetric four-grating compressors, and then the smoothed pulse is used for post-compression. The simulation results indicate that this method can effectively remove hot spots from laser pulses and maintain high peak power enhancement in post-compression.
压缩后可通过缩短脉冲持续时间有效进一步提高激光脉冲的峰值功率。这已在各种能量范围和中心波长下进行了研究。然而，由于泵浦激光器、不完善的光学元件以及光学布局中的灰尘，高峰值功率激光脉冲的空间强度分布通常是不均匀的。在压缩后，B积分与强度成正比，并且在光谱展宽阶段会引起波前畸变，导致聚焦强度降低。此外，在此过程中光束强度可能会受到强烈调制，光束不均匀性会加剧，从而对光学元件造成损坏并限制高峰值功率增强的实现。在本研究中，为应对这些挑战，首先通过使用棱镜对或非对称四光栅压缩器引入空间色散来平滑激光脉冲，然后将平滑后的脉冲用于压缩后处理。模拟结果表明，该方法可以有效去除激光脉冲中的热点，并在压缩后处理中保持高峰值功率增强。
