近日，韩国蔚山科学技术院的Min Sup Hur及其研究小组与光州科学技术院的Hyyong Suk，以及苏格兰大学物理联盟&英国斯特拉斯克莱德大学的Dino A. Jaroszynski等人合作，并取得一项新进展。经过不懈努力，他们提出利用密度梯度等离子体压缩激光脉冲实现艾瓦到泽瓦激光器的新方法。相关研究成果已于2023年11月13日在国际知名学术期刊《自然—光子学》上发表。

该研究团队提出了一种基于非均匀等离子体色散空间变化的超高功率激光脉冲压缩新方法。当一负频率啁啾的长激光脉冲从过密等离子体板的密度斜坡反射时，即可实现脉冲压缩。随着纵向密度的增加，激光脉冲前导部分的高频光子比低频光子更深入等离子体区域，导致脉冲压缩，其方式与啁啾镜类似。

原理验证模拟使用胞元粒子模拟代码进行，预测可将2.35ps的激光脉冲压缩至10.3fs，压缩比率高达225。由于等离子体在高强度下稳定可靠，与常用于啁啾脉冲放大的固态光栅不同，因此该方法可作为压缩器，用于达到艾瓦（EW）或泽瓦（ZW）级别的峰值功率。

附：英文原文

Title: Laser pulse compression by a density gradient plasma for exawatt to zettawatt lasers

Author: Hur, Min Sup, Ersfeld, Bernhard, Lee, Hyojeong, Kim, Hyunsuk, Roh, Kyungmin, Lee, Yunkyu, Song, Hyung Seon, Kumar, Manoj, Yoffe, Samuel, Jaroszynski, Dino A., Suk, Hyyong

Issue&Volume: 2023-11-13

Abstract: We propose a new method of compressing laser pulses to ultrahigh powers based on spatially varying dispersion of an inhomogeneous plasma. Here, compression is achieved when a long, negatively frequency-chirped laser pulse reflects off the density ramp of an over-dense plasma slab. As the density increases longitudinally, high-frequency photons at the leading part of the laser pulse penetrate more deeply into the plasma region than lower-frequency photons, resulting in pulse compression in a similar way to that by a chirped mirror. Proof-of-principle simulations performed using particle-in-cell simulation codes predict compression of a 2.35ps laser pulse to 10.3fs—a ratio of 225. As plasma is robust and resistant to damage at high intensities—unlike solid-state gratings commonly used in chirped-pulse amplification—the method could be used as a compressor to reach exawatt or zettawatt peak powers.

DOI: 10.1038/s41566-023-01321-x

Source: https://www.nature.com/articles/s41566-023-01321-x