非链式脉冲DF激光器放电技术研究

	非链式脉冲DF激光器放电技术研究
其他题名	Reach on discharge technique of non-chain pulsed DF laser
	王旭
学位类型	硕士
导师	谢冀江
	2015-10
学位授予单位	中国科学院大学
学位专业	光学工程
关键词	Df激光器放电技术有限元分析均匀场电极
摘要	中红外波段（3~5μm）是大气传输窗口，而且许多原子和分子的吸收峰也处于这一波段，人体骨骼和肌肉对于这一波段具有选择吸收性。因此中红外波段的激光光源在军事、激光雷达、大气探测、医疗等领域具有极高的应用价值和前景。目前，非链式脉冲DF激光器是该波段可以输出能量最高的激光器，而且其相对于链式反应的连续DF激光器来说，具有结构紧凑、操作简单、反应可控、光束质量好等优势，受到国内外众多研究者的关注。本文对非链式脉冲DF激光器的放电技术进行了研究。放电技术是非链式脉冲DF激光器的核心技术，直接决定着激光器的输出能量和电光转换效率。本文对紫外预电离与自引发放电两种放电方式进行了对比研究。首先使用有限元分析法模拟了两种放电方式激光器的电极间电场分布。紫外预电离放电要求使用均匀场电极以提高注入能量、增大放电体积。计算了Chang氏电极、紧凑型Chang氏电极和Ernst电极三种均匀场电极的电场分布，在相同的设计要求下Ernst电极的电极表面电场均匀区域最大，其次是紧凑式Chang氏电极，而Chang氏电极的电极表面电场均匀区域最小。计算了自引发放电电极间电场分布，阴极表面的毛刺对放电区宏观电场均匀性基本无影响，只在微米尺度上形成一系列分立的高电场区域。粗糙阴极表面的强电场区域不仅加强了电子的电场能量，还加强了阴极金属的场致发射作用，相对于周围低电场区域有更多的电子进入放电区，从而使放电开始阶段可以形成初始放电通道。通过实验研究两种放电方式的DF激光器，对两种激光器的输出能量进行优化实验，对比分析两种放电方式的DF激光器输出能量与电光转换效率。记录紫外预电离放电非链式DF激光器的放电照片，证实了均匀的电场分布可以得到稳定的体放电，并且可以增大放电体积，同时提高注入放电区的能量。通过分析两种放电方式，发现自引发放电在增大非链式DF激光器放电体积方面更具优势。
其他摘要	Mid-infrared band, in the spectral range 3~5μm, is the infrared atmospheric transparency window covering the absorption peaks of many atoms and molecules. Besides, the absorptivity of bones and muscles is different in the mid-infrared band. Thus mid-infrared laser has high application value and future in military, laser radar, atmospheric sounding, medical treatment, etc. Currently，non-chain pulsed DF laser has the highest output energy in this band. Furthermore it has the advantages of compact structure, simple operation, controllable reaction, good beam quality, etc. And it receives the domestic and foreign multitudinous researcher's attention. In this paper, the discharge technique of non-chain pulsed DF laser is studied. Discharge technique is the core technology of the non-chain pulsed DF laser, which determines the output energy and the electro-optical conversion efficiency of the laser directly. In this paper, the UV pre-ionization and the self-initiated volume discharge are compared. Firstly, the electric field distribution of two kinds of discharge modes is simulated by finite element analysis. UV pre-ionization discharge requires using uniform field electrode to increase the injection energy and discharge volume. The electric field distribution of three kinds of uniform field electrode, Chang electrode, compact Chang electrode and Ernst electrode were calculated. At the same design requirements, the area of uniform electric field on the surface of the Ernst electrode is the largest, followed by the compact Chang electrode, and the Chang electrode is the smallest. And then the electric field distribution of the self-initiated volume discharge electrode is calculated. The burrs on the cathode surface will form a series of higher electric field, but not affect the uniformity of the electric field in the discharge area. The strong electric field region of the rough cathode surface not only strengthens the electric field energy of the electron, but also strengthens the field emission of the cathode. There are more electrons in the discharge area relative to the low electric field area, so that the initial discharge channel can be formed. Two kinds of discharge modes of DF laser are studied by experiment, optimizing the output energy of two lasers, compared and analyzed the output energy and the efficiency of electro-optical conversion about two discharge modes of DF laser. The discharge photos of the UV non-chain DF laser are recorded. It is proved that the stable volume discharge can be obtained, and the discharge volume and the injected energy can be increased in the uniform electric field distribution. By analyzing the two discharge modes, it is found that the self-initiated volume discharge has more advantages to enhance the discharge volume of non-chain DF laser.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/49328
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	王旭. 非链式脉冲DF激光器放电技术研究[D]. 中国科学院大学,2015.

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