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chi20181128上海光机所沈百飞557449Light-matter interaction has been one of the crucial concerns in physics since the invention of laser by T. Maiman in 1960. With the rapid development of laser technology, the laser intensity has increased significantly, lasers with focal intensity above 1022 W/cm2 and duration of single pulse shorter than 10 fs has been achieved in laboratory. In such condition, material are ionized to be plasma, the temperature,pressure and density of plasma in lab are similar to the case in astrophysics. Thus, we can simulate some astrophysical phomenon by laser plasma interaction in labratory,such as, jet, magnetic reconnection, production of positrons and electrons, phase change of planet core and asteroid strikes. On the other hand, discovered by Allen et al. in 1992,the vortex laser pulse with orbital angular momentum and donut intensity distribution is attracting continuous attention in various aspects, such as such as information encoding and optical manipulation.Moreover, intense vortex has been researched in recent years, which may be potential application in many fields, such as stimulated emission depletion microscopy, vortex high order harmonics generation and particles acceleration. Based on the above points, the following aspects of work has been done in this paper: 1,Crater-like structures are experimentally studied with an ultrashort,ultraintense laser pulse with an intensity of 1.5×1018 W/cm2, irradiating borosilicate glass targets. The morphology of the crater-like structures is measured accurately using a three-dimensional laser scanning confocal microscope and a scanning electron microscope. The experimental results indicate that a circular bowl shape is formed with a depth-to-diameter ratio of about 1/5, which is similar to that of meteorite impact craters. A plasma fireball model is applied to analyze the experimental results. Studies show that catastrophic asteroid strikes may be investigated by irradiating foils with intense laser pulses, which verifies the universality of depth-to-diameter ratio in a new parameters region of laser intensity. 2,The interference of a relativistic vortex laser is investigated for the case when a linearly polarized Laguerre–Gaussian pulse impinges on a double-slit solid target, which extends the usual double-slit interference to the regime of relativistic intensity. Three-dimensional particle-in-cell simulation results show that the interference fringes of high-order harmonics are twisted, similar to that of the fundamental vortex laser. The twisting order of the interference pattern is determined by the order of the vortex high-order harmonics, which can be explained by the classic double-slit interference models. 3,The interference of a relativistic vortex laser is investigated for the case when a linearly polarized Laguerre–Gaussian pulse impinges on a double-slit solid target, which extends the usual double-slit interference to the regime of relativistic intensity. Three-dimensional particle-in-cell simulation results show that the interference fringes of high-order harmonics are twisted, similar to that of the fundamental vortex laser. The twisting order of the interference pattern is determined by the order of the vortex high-order harmonics, which can be explained by the classic double-slit interference models.2019atalunwen219128112125988Intense laser,;Crater-structure,;Relativistic vortex laser;High order harmonics; Optical vortex arrayIntense Ablation Glass and Interference of Intense Vortex Laser超强激光烧蚀玻璃和超强涡旋光的干涉自1960 年梅曼( T. Maiman)成功研制出世界上第一台激光器开始,激光与物质的相互作用就是人们一直致力研究的核心物理问题之一。随着激光技术的快速发展, 激光的强度得到了显著的提高, 实验室已经能够获得聚焦强度超过10<22>上标 W/cm2、单脉冲宽度小于 10 fs 的激光脉冲。 如此强的激光和物质相互作用时,物质状态会变成等离子体状态, 进入了相对论强激光与等离子体相互作用的领域。一方面,在强激光的作用下,物质被电离,其所产生等离子体的压强、温度、密度等参数与一些天体物理中的等离子体参数相似, 利用这种相似性,一些天体物理过程可以在实验室中进行模拟, 如喷流、 磁重联、宇宙中正负电子对的产生、星体内核物态变化以及陨石撞击等。 相比于传统的天文观测和光谱分析,实验室天体物理具有成本低、 重复性好、 条件可控等优点。 另一方面, 1992 年Allen 等人发现了一种新型模式的光——涡旋光, 涡旋光可以携带角动量, 且它的强度分布是中空的, 由于涡旋光这些特点,使涡旋光在信息传输和光学微观操控等领域有重要的应用价值。 此外, 超强超短涡旋光和物质相互作用近几年也备受人们关注,在超分辨成像、涡旋高次谐波产生、粒子加速等领域有重要的应用。 基于以上内容,本论文主要做了以下几个方面的工作: 1,用超强激光脉冲( 1.5×1018 W/cm2 ) 烧蚀硼酸盐玻璃,在玻璃表面形成了类似于天体物理的陨石坑状结构。我们用三维激光扫描仪和电子显微镜对玻璃烧蚀坑的形貌进行了测量。实验结果表明在烧蚀坑的中间有一 个碗状结构,碗状结构的深度和直径比是 1/5, 这个比值和天体物理中的简单陨石坑的深径比很接近。我们用等离子体火球模型对实验结果进行了分析。研究表明我们可以利用超强激光烧蚀硼酸盐玻璃来模拟天体物理中的陨石坑形成,并且在新的参数区域内验证了深径比的普适性。 2,传统的双缝干涉实验,大都是在弱光下进行的。我们首次把双缝干涉扩展到相对论强度领域,在相对论强度领域,激光和物质相互作用会有一些非线性效应,诸如高次谐波的产生。 我们用三维 Particle-in-cell 用一束相对论强度的涡旋光和双缝等离子体靶相互作用。模拟结果显示基频和三倍频的涡旋光干涉条纹会弯曲。弯曲的程度和谐波的阶数有关。 我们用经典的干涉理论和角动量守恒解释了这一现象。 3,光涡旋阵列在信息编码和传输,光镊等方面有重要的应用,但传统的光涡旋阵列对应的波长都在可见光波段。我们利用两束相对论的涡旋光分别和两个薄膜等离子体靶相互作用,高次谐波产生并且在靶后相互干涉,通过分析高次谐波的干涉图样,该图样呈花瓣状分布,这种分布可以看做光涡旋阵列的一种,且花瓣的个数跟谐波的拓扑荷数有关,我们提供了一种产生超高超强高次谐波光涡旋阵列的方法。该阵列可以在短波长,高强度的区域有潜在的应用。超强激光;陨石坑状结构;相对论涡旋光;双缝干涉;高次谐波;光涡旋阵列中国科学院上海光学精密机械研究所张浩光学博士
中文题目: 超强激光烧蚀玻璃和超强涡旋光的干涉
外文题目: Intense Ablation Glass and Interference of Intense Vortex Laser
作者: 张浩
导师姓名: 沈百飞
学位授予机构: 中国科学院上海光学精密机械研究所
答辩时间: 20181128
中文关键词:
超强激光;陨石坑状结构;相对论涡旋光;双缝干涉;高次谐波;光涡旋阵列
英文关键词:
Intense laser,;Crater-structure,;Relativistic vortex laser;High order harmonics; Optical vortex array
中文摘要:
英文摘要:
文献类型:学位论文
学位级别: 博士
正文语种: chi
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