本文選題：全腔水冷 + 板條激光器�。� 參考：《哈爾濱工業(yè)大學(xué)》2015年碩士論文

【摘要】：高功率固體激光器以體積小、可靠性強(qiáng)、轉(zhuǎn)換效率高等著稱,已被廣泛應(yīng)用于軍事、醫(yī)療、工業(yè)加工等多個(gè)領(lǐng)域。其中,相比較于棒狀固體激光器,板條狀固體激光器能夠獲得具有更高光束質(zhì)量的光,更高的輸出功率以及更高的效率,一直以來都深受人們的關(guān)注。固體激光器工作時(shí),會(huì)有相當(dāng)大的一部分泵浦光轉(zhuǎn)化為熱滯留在激光介質(zhì)內(nèi),使其溫度升高。而對(duì)激光介質(zhì)的冷卻,通常為外部冷卻,這樣將會(huì)導(dǎo)致介質(zhì)內(nèi)溫度不均勻分布的現(xiàn)象,溫度的不均分布和因其產(chǎn)生的熱應(yīng)力都將會(huì)引起一系列熱效應(yīng)問題。因此,對(duì)激光介質(zhì)的溫度及應(yīng)力等的分布狀況進(jìn)行研究是很有必要的。本課題采用氙燈泵浦8板條輻射狀激光增益介質(zhì)(8個(gè)板條呈“米”字型排列),能有效增加泵浦面積和激光介質(zhì)的散熱面積,這樣既能夠有效提高激光器的轉(zhuǎn)換效率又能有效減弱其熱效應(yīng)。同時(shí),為了提高輸出光的峰值功率,擴(kuò)大激光器應(yīng)用范圍,本課題加入了被動(dòng)調(diào)Q技術(shù)。本文主要研究的內(nèi)容包括激光介質(zhì)溫度及熱應(yīng)力分布的理論分析及數(shù)值模擬,被動(dòng)調(diào)Q的相關(guān)理論及實(shí)驗(yàn)研究,激光器聚光腔的優(yōu)化設(shè)計(jì),具體研究?jī)?nèi)容總結(jié)如下:(1)給出了本課題研究的背景、意義,總結(jié)概述了板條狀固體激光器國(guó)內(nèi)外研究現(xiàn)狀,概括闡述了板條狀激光介質(zhì)熱效應(yīng)的相關(guān)問題及一些制冷方式,并對(duì)被動(dòng)調(diào)Q激光器的研究概況做了簡(jiǎn)單總結(jié)。(2)簡(jiǎn)單介紹了溫度場(chǎng)及熱應(yīng)力應(yīng)變場(chǎng)的描述等問題,理論研究了輻射板條激光介質(zhì)的熱分析問題,并通過運(yùn)用ANSYS軟件對(duì)輻射狀板條激光介質(zhì)在不同條件下的溫度及熱應(yīng)力分布做了有限元模擬分析,并最后給出了實(shí)況下激光介質(zhì)的溫度及應(yīng)力分布的有限元模擬結(jié)果。(3)闡述了被動(dòng)調(diào)Q的基本原理,被動(dòng)調(diào)Q晶體Cr4+:YAG的基本性質(zhì)、光譜特性、能級(jí)結(jié)構(gòu)及可飽和吸收特性,給出了晶體Cr4+:YAG被動(dòng)調(diào)Q的速率方程,并對(duì)其進(jìn)行了仿真分析,最后利用速率方程對(duì)調(diào)Q激光輸出特性進(jìn)行相關(guān)求解和分析。(4)對(duì)輻射板條激光器的聚光腔部分進(jìn)行了優(yōu)化設(shè)計(jì),實(shí)現(xiàn)了輻射板條激光器的自由運(yùn)轉(zhuǎn)。利用矩陣光學(xué)理論并借助MATLAB軟件分析了光斑聚焦特性,在此基礎(chǔ)上確定了調(diào)Q晶體的具體位置,并進(jìn)行了輻射板條激光器的被動(dòng)調(diào)Q實(shí)驗(yàn)。
[Abstract]:High power solid-state lasers are known for their small size, high reliability and high conversion efficiency. They have been widely used in military, medical, industrial processing and other fields.Compared with the rod solid state laser, the strip solid state laser can obtain higher beam quality, higher output power and higher efficiency.When the solid-state laser is working, a considerable part of the pump light will be converted into hot trapped in the laser medium, and the temperature will rise.However, the cooling of laser medium is usually external cooling, which will lead to the phenomenon of uneven distribution of temperature in the medium, and the uneven distribution of temperature and the thermal stress will cause a series of thermal effects.Therefore, it is necessary to study the temperature and stress distribution of laser medium.In this paper, the Xenon lamp is used to pump 8 strip radiative laser gain media (8 strips are arranged in "meters" shape), which can effectively increase the pump area and the heat dissipation area of the laser medium.In this way, the conversion efficiency of the laser can be improved and the thermal effect can be weakened effectively.At the same time, in order to increase the peak power of output light and expand the application range of laser, passive Q-switched technology is added in this paper.The main contents of this paper include the theoretical analysis and numerical simulation of the temperature and thermal stress distribution of laser medium, the theoretical and experimental study of passive Q-switching, the optimization design of laser condenser.The specific research contents are summarized as follows: (1) the background and significance of the research are given, the research status of plate solid state laser at home and abroad is summarized, and the related problems and some refrigeration methods of the thermal effect of strip laser medium are summarized.A brief summary of the research of passive Q-switched laser is given. The description of temperature field and thermal stress-strain field is briefly introduced, and the thermal analysis of radiation slab laser medium is studied theoretically.By using ANSYS software, the temperature and thermal stress distribution of radiative lath laser medium under different conditions are simulated and analyzed by finite element method.Finally, the finite element simulation results of temperature and stress distribution of laser medium are given. The basic principle of passive Q-switched crystal Cr4: YAG is described. The basic properties, spectral characteristics, energy level structure and saturable absorption characteristics of passively Q-switched crystal Cr4: YAG are described.The rate equation of passively Q-switched crystal Cr4: YAG is given and simulated. Finally, the output characteristics of Q-switched laser are solved and analyzed by using the rate equation.The free operation of the radiation lath laser is realized.Based on matrix optics theory and MATLAB software, the spot focusing characteristics are analyzed, and the specific position of Q-switched crystal is determined, and the passive Q-switching experiment of the radiation slab laser is carried out.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TN248.1

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本文編號(hào)：1741063