首页 | 官方网站   微博 | 高级检索  
     

等离子体光栅靶的表面粗糙度对高次谐波产生的影响
引用本文:李夏至,邹德滨,周泓宇,张世杰,赵娜,余德尧,卓红斌.等离子体光栅靶的表面粗糙度对高次谐波产生的影响[J].物理学报,2017,66(24):244209-244209.
作者姓名:李夏至  邹德滨  周泓宇  张世杰  赵娜  余德尧  卓红斌
作者单位:1. 国防科学技术大学理学院, 长沙 410073;2. 上海交通大学IFSA协同创新中心, 上海 200240
基金项目:国家重点基础研究发展计划(批准号:2013CBA01504)、国家自然科学基金(批准号:11375265,11475259,11675264)和科学挑战计划(批准号:JCKY2016212A505)资助的课题.
摘    要:极紫外光和软X射线由于其波长和脉冲持续时间极短,可用于超快物理过程和物质微观结构的探测.最近几年,研究人员发现激光和等离子体相互作用可以产生持续时间极短(阿秒)且相干性较好的高次谐波辐射,其波长可接近甚至达到水窗波段.然而,实验研究指出,理论上应出现的一些谐波在实验中并没有出现.本文针对超短超强激光与非理想条件下的等离子体光栅靶相互作用产生高次谐波的物理过程进行了理论分析和粒子模拟.研究结果表明,等离子体光栅的周期性结构对于高次谐波的频谱和辐射角分布存在显著调制效果.光栅靶表面粗糙度直接影响光栅的光学调制效果,改变高次谐波的频谱分布和辐射角分布.理想光栅条件下,满足光栅匹配条件的特定阶数谐波明显获得增强,且辐射张角集中在平行靶面的方向.靶表面粗糙度的出现,导致光栅匹配条件失效,高次谐波能量向各阶分散且辐射张角逐渐偏离靶表面方向.研究结果较好地解释了实验中观测到的谐波频谱分布,为进一步的研究提供了一定参考.

关 键 词:高次谐波  超强激光  等离子体光栅  表面电流模型
收稿时间:2017-06-11

Effect of plasma grating roughness on high-order harmonic generation
Li Xia-Zhi,Zou De-Bin,Zhou Hong-Yu,Zhang Shi-Jie,Zhao Na,Yu De-Yao,Zhuo Hong-Bin.Effect of plasma grating roughness on high-order harmonic generation[J].Acta Physica Sinica,2017,66(24):244209-244209.
Authors:Li Xia-Zhi  Zou De-Bin  Zhou Hong-Yu  Zhang Shi-Jie  Zhao Na  Yu De-Yao  Zhuo Hong-Bin
Affiliation:1. College of Science, National University of Defence Technology, Changsha 410073, China;2. IFSA Collaborative Innovation Center, Shanghai Jiao Tong University, Shanghai 200240, China
Abstract:Extreme ultra-violet (XUV) light and soft X-ray are widely used to detect the microscopic structure and observe the ultra-fast physical process. It is found that high order harmonic with the frequency as high as that of the waterwindow waves and the pulse duration as short as attosecond can be obtained in the laser-plasma interaction. Due to these features, high order harmonic (HH) is a promising alternative to generating ultra-short XUV light and X-ray. Recently, HHs have been observed in the experiments. However, the frequency spectrum is not complete compared with the results predicted theoretically and numerically. It might relate to the damage of the grating target surface by a long laser repulse. In this article, the effect of target surface roughness on the high order generation (HHG) in the interaction between ultra-intense laser pulse and grating targets is investigated by surface current model and particle-in-cell simulations. We find that both the spatial and spectral domains of harmonics are modulated by the periodical structure of the grating due to the optical interference. The roughness on the surface significantly distorts the modulation effect and leads to different radiation angle and spectral distributions. For the ideal grating, only harmonics satisfying matching condition in a certain direction can be enhanced and the radiation power is restricted in the direction nearly parallel to the target surface. When the surface roughness of the grating target is considered, the matching condition is not valid and the harmonics are scattered into the direction away from the target surface. Comparing with the ideal grating target, most of the harmonic energy is concentrated in the low order harmonics and the intensities of the harmonics decrease rapidly with increasing HH order when surface roughness is considered. The results show good consistence with the phenomena observed in previous experiments and provide the technical reference for exploring the future applications of HHs and HHG.
Keywords:high-order harmonics  ultra-intense laser pulse  plasma grating target  surface current model
本文献已被 CNKI 等数据库收录!
点击此处可从《物理学报》浏览原始摘要信息
点击此处可从《物理学报》下载免费的PDF全文
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号