【作者】 肖楠；

【导师】 姜宗福；

【作者基本信息】 国防科学技术大学 ， 光学工程， 2009， 博士

【摘要】 受化学物质氧化-还原反应发出强闪光的启发,以烟火药燃烧发光机理研究为基础,进行了烟火药特征辐射光谱与激光介质吸收光谱匹配的尝试和新配方烟火泵浦源药剂的研究,继而设计制备了烟火泵浦激光器实验装置并对其结构和出光性能作出改进,并与气体放电灯和阳光泵浦源比较,探讨了这种激光器的应用前景。出于研制新型高效烟火光源的需要,对各种类型氧化剂和可燃剂进行总体和针对性实验,发现了氧化剂、可燃剂与辐射强度、发射光谱之间定性的对应关系。用CEA（Chemical Equilibrium with Applications）计算了烟火药燃烧平衡态热力学参数和产物组成,并与实验结果对照,进而对烟火药的发光机理作出分析,认为烟火药的连续谱和分立谱都是热激发的结果,受黑体辐射定律支配,连续谱体现为燃烧体系的平衡温度,分立谱强度由偏离平衡的局部瞬态高温决定,特征波长分布由气体发射率本征分布决定。这个结论对认识烟火药发射光谱的本质和指导药剂研究具有重要意义。由于烟火药的发射光谱轮廓对激光器的光泵浦效率影响较大,本文分析了烟火药发射光谱轮廓的成因和影响因素,并对照激光介质吸收光谱随激活离子和基质结构变化的规律,在综合考虑了物理、化学、光学性能和技术现状后,选择了磷酸盐Nd玻璃为本文实验的激光介质。针对该介质研制了一组发射混合光谱的烟火泵浦源药剂,与以前报道的完全不同,其中A#配方能够稳定出光,其主要化学组成为:RbNO₃、Ba（NO₃）₂、KClO 4、NaNO₃和Al/Mg。在药剂研究的基础上,设计制备了烟火泵浦激光器实验装置。通过引入雾化Mg粉部分取代Al/Mg合金成功提高了燃烧速度、峰值辐射强度以及能量转化效率。考虑到光束的空间传播特性和燃烧产物中凝聚态成份对光路的影响,研究了激光能量随质量和分布的变化规律,发现大量药柱集中在少量电阻丝上的排布方式能量利用率高,药柱间距小于药柱到介质保护管表面距离时,泵浦比较均匀。出光实验得到结果为:用2.52g药剂反应获得1.053μm激光1.012 J,脉宽约40ms。将烟火泵浦源与其它光泵浦源比较,认为其总辐射强度低于Xe灯,但光谱效率可能超过Ke灯和碱金属灯,总的来说其泵浦效果应该能与气体放电灯相当;烟火泵浦源和阳光光源一样,在电能不便利的场合十分有用,前者在使用上更加灵活、方便。在对烟火药发光特征和激光器结构研究的基础上,提出提高现有烟火光源的燃烧速度和点火同步性以获得高峰值辐射强度,并且降低自吸效应以提高光谱效率及能量利用率的泵浦源改进方法,以改进后的泵浦源激励掺Nd³⁺氟化物激光陶瓷的烟火泵浦激光器方案将大大提高现有烟火泵浦激光器的能量和峰值功率。更多还原

【Abstract】 Redox reaction of chemical materials gives out intense light. Enlightened by this fact, study of matching between pyrotechnic reaction emission spectrum and laser medium absorption spectrum was made and a new prescription of pyrotechnical was prepared based on the study of pyrotechnic reaction radiation mechanism. Pyrotechnically pumped laser was fabricated, and its structure and optical ability were improved. Future application of the laser was studied by comparison with gas discharge lamp and solar pump source.To satisfy the demands of developing effective new pyrotechnic light source, genaral and special experiments on all kinds of oxidant and fuel were made. Relationship beween oxidant, fuel and radiantion intensity, emission spectrum was given out. Burning equilibrium state thermodynamic parameter and producion ingredient of pyrotechnical were calculated by CEA （chemical Equilibrium with Applications） program, and compared with the experiment results. Analysis of radiation mechanism considers that either continuous spectum or line spectra was the result of thermal excitation. They all obey the rule of black-body radiation. Continuouse spectrum was scaled by equilibrium temperature, intensity of line spectra decided by the transient state high temperature of deviated gas. Spectral distribution of line spectra was decided by emissivity of gas. The conclusion is important for apprehension of pyrotechnic reaction emission spectrum and study of pyrotechnic preparation.Formation and influencing factor of pyrotechnic emission outline was analysed because of its significance to the optical pump efficiency of laser. The absorption spectrum of laser medium affected by the actication center and ground substance, so phosphate Nd glass was selected for experiment in the paper after comprehensive consideration of physical, chemical, optical property and technical actuality. A set of prescription which give out mixed spectrum were prepared for the laser medium, they are different completely with the prescription used before. Among them, A# prescription gave out laser steadily. The chemical composition of A# is: RbNO₃, Ba（NO₃）₂, KClO₄, NaNO₃ and Al/Mg.Experiment equipment of pyrotechnically pumped laser was designed and fabricated based on the prescription study. Burning speed, peak radiation intensity and optical efficiency were improved by replacing half of Al/Mg with pulverized Mg powder. In view of the space transmit character of light and obstruction of condensed phase in production, law on laser energy varied with pyrotechnical distribution and weight was studied. It was found even pump is achieved by distribution manner that poles concentrated to few wires and the interval between poles is smaller than the spacing between poles and quartz tube. The best result was: 1.012J laser at 1.053μm which lasting 40ms was achieved by 2.52g pyrotechnical powder.Comparisons with other optical pump source suggest that, the genaral radiation of pyrotechnical pump source is lower than Xe lamp, but the efficiency shouled exceed Ke lamp and alkali metal lamp. In genaral, the pump source corresponds to gas discharge lamp. Pyrotechnical pump source as well as solar pump source is very useful when electric energy dosen’t available; former is more expedient and convenient.Based on the study of pyrotechnic optical property and laser structure, method to ameliorate the pyrotechnical pump source wase put forward: improving the burning rate and ignition synchronism to acquire higher peak radiation intensity, and depressing the self-absorption effect to raise the spectrum efficiency and energy conversion efficiency. The fluoride Nd laser ceramic excited with the improved pump source will be a promise scheme to increase the laser energy and peak power greatly.更多还原