长脉冲激光致增透熔石英窗口损伤的特性研究

发布时间：2018-06-10 09:52

本文选题：长脉冲激光 + 激光损伤特性　；参考：《长春理工大学》2017年硕士论文

【摘要】：随着激光技术的发展,对光学元件的各项指标要求也逐步提高,其抗激光损伤能力是非常重要的一项。长脉冲激光因其单脉冲能量大、损坏能力强等特点,相比短脉冲激光而言,可以对靶材造成更大的损伤效果。因此,本文从理论模拟和实验研究两个方面,分析了长脉冲激光辐照增透熔石英窗口时温度场、应力场变化情况,并对损伤特性进行分析。理论模拟方面,基于热传导理论、弹性力学理论和有限元法,模拟单脉冲以及脉冲串激光辐照增透熔石英窗口的物理过程。通过热传导理论、弹性力学理论计算材料内的温升过程和应力分布情况。从空间和时间两个方面研究了热应力的变化情况,能量密度为3185J/cm2时中心点最高温度约为1360K,同时完成改变单一参量时增透熔石英窗口材料温升及应力变化情况。实验研究方面,测量分析了长脉冲激光辐照增透熔石英时中心点温度变化,搭建了长脉冲激光辐照熔石英时在线应力测量实验系统,利用马赫-曾德尔干涉的原理,获得熔石英内部产生应力时干涉条纹的变化过程,通过应力与应变的关系以及干涉原理对干涉条纹变化进行计算与分析,得到熔石英在线应力实时变化过程,能量密度为1943J/cm2时,实验计算的σx最大值为17.97MPa,σz最大值为4.8MPa;讨论了材料内部的残余应力的分布情况,以及激光辐照后材料的损伤形貌,损伤面积的增长规律,总结了激光损伤增透熔石英窗口的规律和特性。
[Abstract]:With the development of laser technology, the requirements of optical components are gradually improved, and its ability to resist laser damage is very important. Long pulse laser can cause more damage to target than short pulse laser because of its large energy and strong damage ability. Therefore, in this paper, the temperature field and stress field of quartz window irradiated by long pulse laser are analyzed from two aspects of theoretical simulation and experimental study, and the damage characteristics are analyzed. In theoretical simulation, based on heat conduction theory, elastic theory and finite element method, the physical process of antireflective quartz window irradiated by single pulse and pulse string laser is simulated. The temperature rise process and stress distribution in the material were calculated by heat conduction theory and elastic theory. The variation of thermal stress in space and time is studied. The maximum temperature of center point is about 1360K when the energy density is 3185J / cm ~ 2, and the temperature rise and stress change of quartz window material with single parameter change. In the aspect of experimental research, the temperature change of the center point of antireflective fused quartz irradiated by long pulse laser is measured and analyzed. The on-line stress measurement system of fused quartz irradiated by long pulse laser is set up, and the principle of Mach Zehnder interference is used. The variation process of interference fringes is obtained when stress is produced in fused quartz. By calculating and analyzing the variation of interference fringes based on the relationship between stress and strain and interference principle, the real-time process of in-line stress variation of fused quartz is obtained, when the energy density is 1943 J / cm ~ 2, The maximum 蟽 _ x and 蟽 _ z are 17.97 MPA and 4.8 MPA respectively, and the distribution of residual stress in the material, the damage morphology and the growth law of damage area after laser irradiation are discussed. The law and characteristics of laser damage antireflection and melting quartz window are summarized.
【学位授予单位】：长春理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN249

【参考文献】