本文選題：長脈沖激光 + 激光損傷特性�。� 參考：《長春理工大學》2017年碩士論文

【摘要】：隨著激光技術的發(fā)展,對光學元件的各項指標要求也逐步提高,其抗激光損傷能力是非常重要的一項。長脈沖激光因其單脈沖能量大、損壞能力強等特點,相比短脈沖激光而言,可以對靶材造成更大的損傷效果。因此,本文從理論模擬和實驗研究兩個方面,分析了長脈沖激光輻照增透熔石英窗口時溫度場、應力場變化情況,并對損傷特性進行分析。理論模擬方面,基于熱傳導理論、彈性力學理論和有限元法,模擬單脈沖以及脈沖串激光輻照增透熔石英窗口的物理過程。通過熱傳導理論、彈性力學理論計算材料內(nèi)的溫升過程和應力分布情況。從空間和時間兩個方面研究了熱應力的變化情況,能量密度為3185J/cm2時中心點最高溫度約為1360K,同時完成改變單一參量時增透熔石英窗口材料溫升及應力變化情況。實驗研究方面,測量分析了長脈沖激光輻照增透熔石英時中心點溫度變化,搭建了長脈沖激光輻照熔石英時在線應力測量實驗系統(tǒng),利用馬赫-曾德爾干涉的原理,獲得熔石英內(nèi)部產(chǎn)生應力時干涉條紋的變化過程,通過應力與應變的關系以及干涉原理對干涉條紋變化進行計算與分析,得到熔石英在線應力實時變化過程,能量密度為1943J/cm2時,實驗計算的σx最大值為17.97MPa,σz最大值為4.8MPa;討論了材料內(nèi)部的殘余應力的分布情況,以及激光輻照后材料的損傷形貌,損傷面積的增長規(guī)律,總結(jié)了激光損傷增透熔石英窗口的規(guī)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.
【學位授予單位】：長春理工大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TN249

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本文編號：2002803