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chi20190524上海光机所梁晓燕557597Over the past two decades, ultra-intense and ultra-short laser technology has made great progress. Because of its unique advantages such as ultra-fast time resolution and ultra-intense peak power, ultra-intense and ultra-short laser can play a significant role in many frontier scientific fields and interdisciplinary fields. At present, many countries in the world are building or have built ultra-intense and ultra-short laser devices with output power of several petawatt level. With the development of focusing technology, the output power density of petawatt laser device can reach 1022W/cm2 by reasonable focusing means, which can create unprecedented extreme physical conditions in the laboratory environment. This makes the study of the interaction between light and matter enter the field of relativistic optics, and greatly promotes the acceleration of plasma physics, nuclear medicine and energetic particles. And the development of strong field physics such as antimatter research. How to further enhance the focusing power density of ultra-intense and ultra-short laser devices has become an important challenge for researchers in the field of ultra-intense and ultra-short laser. Wavefront distortion is an important factor affecting the focusing power density. Petawatt laser system has a complex structure, including a large number of reflectors, transmission mirrors and other optical devices, and the optical transmission distance is long. The wavefront aberration of the laser beam will be caused by the fabrication surface errors of optical devices, which will deteriorate with the propagation of the laser beam in the laser system, and ultimately affect the focusing performance of the system. Therefore, the research on the generation and evolution of pulse wavefront aberration in petawatt laser system is the premise of wavefront correction experiment, which is of great significance for improving the focusing performance of petawatt laser system. Based on the Shanghai Ultrafast Laser Facility (SULF) built by Shanghai Institute of Optics and Fine Mechanics, the origin and evolution of the wavefront of the whole system are analyzed and studied by measuring the corresponding wavefront distortion value at each important node of the optical path. And other important factors affecting wavefront distortion in the system are analyzed and discussed, including the influence of transmitted beam aperture on wavefront distortion, the influence of mirror clamping stress on wavefront distortion, the influence of Ti-sapphire crystal on wavefront distortion of the system and the influence of adjusting the attitude of off-axis parabolic mirror (OAP) on the wavefront focusing, etc. These work has studied in advance for the later wavefront correction process of SULF system and the improvement of the focusing performance of petawatt laser device. The main research results are as follows: 1. The wavefront measurement device is built at each important node of the optical path of the SULF laser system. The wavefront of the laser system is measured step by step. The types, origin and evolution of the wavefront distortion of the laser system are analyzed. The reasons for the local increase of the wavefront distortion of the nodes of each subsystem are discussed, and the calibration method of the wavefront distortion of the laser system is discussed. The measured data show that the overall level of wavefront distortion in the front part of the laser system is low, and the growth rate is slow. After passing through a 150 mm Ti:sapphire multipass power amplifier, the growth rate is greatly increased. The wavefront correction must be carried out by adaptive optics to improve the focusing ability of the laser device. 2. The influence of mirror clamping stress on wavefront distortion of optical elements such as mirrors in the system is analyzed. On this basis, the structure design of the laser system and the installation mode of optical devices are optimized to reduce the static wavefront distortion variable of the system.Quantitatively measure the wavefront data of the laser beam before and after the incident of laser beam on the Ti-sapphire crystal in the multi-pass amplification optical path, and compare and analyze the wavefront data, and give the correlation analysis of Ti-sapphire crystal's compensation effect on the wavefront distortion of the system. Analyse the influence of adjusting the attitude of off-axis parabolic mirror on wavefront focusing, and simulate the specific effect of deflection and pitch of off-axis parabolic mirror on focusing spot through Zemax model.2019atalunwen219624144812248petawatt system;wavefront evolution;focal spot;Ti:sapphire;off-axis parabolic mirrorResearch on wavefront evolution and related problems for 10-petawatt-level laser system10拍瓦级激光系统波前演变及相关问题研究近二十年来,超强超短激光技术得到了长足发展。由于超强超短激光同时具有的超快时间分辨率及超强峰值功率等独特优点,使其在诸多前沿科学领域及交叉学科中均能发挥显著作用。目前,世界上已有多个国家正在建设或已建成输出功率达到数拍瓦级的超强超短激光装置。伴随着聚焦技术的发展,通过合理的聚焦手段,拍瓦级激光装置的输出功率密度可以达到1022W/cm2,即可在实验室环境中创造出前所未有的极端物理条件,使得对光与物质相互作用的研究范畴进入相对论光学领域,极大地促进了等离子体物理、核医学、高能粒子加速及反物质研究等强场物理研究方向的发展。如何进一步提升超强超短激光装置的聚焦功率密度,也成为现今超强超短激光领域科研工作者的一大重要挑战。 波前畸变是影响聚焦功率密度的重要因素。拍瓦级激光系统结构复杂,包含大量的反射镜、透射镜及其他光学器件,且光路传输距离较长。光学器件加工面型误差等因素会引起光束波前畸变,并随光束在激光系统中传输而恶化,最终影响系统的聚焦性能。因此研究拍瓦激光系统脉冲的波前畸变产生及演变规律是开展波前校正实验的前提,对于拍瓦激光系统聚焦性能提升具有重要意义。本文基于上海光机所在建的上海超强超短激光装置(Shanghai Ultrafast Laser Facility,SULF),通过在光路各重要节点处测量对应的波前畸变值,对整个系统波前起源及演化过程进行分析研究,并给出波前畸变的产生原因及演化规律,探寻波前畸变校准方法;同时还对系统中其他影响波前畸变的重要因素进行分析讨论,具体包括镜面装夹应力对系统波前畸变的影响、钛宝石晶体对系统波前畸变的影响以及调整离轴抛物面镜(Off-axis Parabolic Mirror,OAP)姿态对波前聚焦的影响等,为SULF系统后期的波前校正过程及拍瓦激光装置聚焦性能提升做好前期研究工作。主要研究成果如下: 1. 在SULF激光系统光路各重要节点处,搭建波前测量装置,逐级测量了激光系统的波前,对激光系统的波前畸变的种类、来源及演化情况进行分析,并讨论各分系统节点波前畸变局部增大的原因,探讨了激光系统波前畸变的校 准方法。测量数据表明,波前畸变在激光系统的前端部分整体水平较低,且增长速度较为缓慢,在通过150mm口径钛宝石多通功率放大器后增长速度大幅度提升,必须经过自适应光学的方法进行波前校正,从而提升激光装置的聚焦能力; 2. 分析了系统中反射镜等光学元件的镜面装夹应力对波前畸变的影响,在此基础上优化激光系统光路结构设计和光学器件的安装方式,降低系统静态波前畸变量;定量测量激光光束在钛宝石多通放大光路中入射钛宝石晶体前后的波前数据,并对波前数据进行对比分析,给出钛宝石晶体对于系统波前畸变的补偿作用的相关分析;分析调节离轴抛物面镜姿态对波前聚焦的影响,并通过Zemax建模模拟出离轴抛物面镜的偏转及俯仰对聚焦光斑的具体影响。拍瓦系统;波前演变;焦斑;钛宝石;离轴抛物面镜中国科学院上海光学精密机械研究所王建业光学工程硕士
中文题目: 10拍瓦级激光系统波前演变及相关问题研究
外文题目: Research on wavefront evolution and related problems for 10-petawatt-level laser system
作者: 王建业
导师姓名: 梁晓燕
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: 20190524
中文关键词:
拍瓦系统;波前演变;焦斑;钛宝石;离轴抛物面镜
英文关键词:
petawatt system;wavefront evolution;focal spot;Ti:sapphire;off-axis parabolic mirror
中文摘要:
英文摘要:
文献类型:学位论文
学位级别: 硕士
正文语种: chi
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