放电引发非链式脉冲DF激光器主机结构研究

	放电引发非链式脉冲DF激光器主机结构研究
	邵明振
学位类型	博士
导师	卢启鹏,邵春雷
	2014-07
学位授予单位	中国科学院大学
学位专业	光学工程
摘要	随着光电对抗领域对高功率中红外波段（3-5μm）相干光源的需求，DF激光越来越受到重视。DF激光输出波段为3.5-4.2μm，中心波长3.8μm，处于军事急需的中波红外波段。其运行方式分为链式和非链式两种，链式DF激光器输出功率虽高，但结构庞大、工作气体易爆炸、维护较难。非链式脉冲DF激光器则避免了连续波运行时易爆炸和腐蚀的缺点，且体积小，易操作，具有高的平均功率和峰值功率。本文研制了一种新型的脉冲DF激光器主机，并利用研制的结果对激光器的输出性能进行了研究分析。脉冲DF激光器主要由真空系统、气体循环冷却系统、光学谐振腔系统、主机支架等组成。其中，风机、换热器、流道、分子筛等组成了气体循环冷却系统。通过改变管路的结构和布局，成功地将快轴流激光器用风机应用到了DF横流激光器上，并采用两台风机并联的方式，为气体的循环流动提供驱动力。光学谐振腔采用平-凹稳定腔，全反镜为球面镜，输出镜为平面镜。谐振腔具有多方位的调整结构来调整光轴的方向。其中，全反镜和输出镜角度的调整采用了方便、快捷的三紧三拉结构。分子筛的作用是吸附工作过程中产生的消激发物质，维持激光器的稳定输出。运用有限元方法对整个机构进行静力学分析，并针对结构中出现的不足进行了优化改进。优化后，结构的最大变形量由2.34mm降至1.67mm，且整体的变形减小。最大应力由296MPa降至193MPa，减轻了应力集中现象，整个结构的强度和刚度均满足工作要求。运用计算流体动力学（CFD）原理对流场中气体的运动状态进行了数值模拟分析。分析的对象包括气体流动时流场中的压力损失，放电区的流速以及均匀性分布等，并根据其影响因素对流道结构进行了优化改进。优化后，采用皮托管测得的放电区气体的流速达到16.3m/s，流速分布纵向最大不均匀度为7.1%，横向最大不均匀度为4.3%，均达到工作要求。利用脉冲DF激光器主机的研制结果进行单脉冲及重频放电试验，在工作气压为8.1KPa，气体比例为SF6：D2=8：1时，单脉冲激光输出能量达到3.6J，重复频率为50Hz时的平均功率达到150W。
其他摘要	With the request of high-power coherent light source in middle-infrared wave bands in the area of photoelectric confrontation, DF lasers have been paid more and more attentions. DF lasers, which have an output wave bands ranging from 3.5-4.2μm and the central wave length of 3.8μm, locate in the middle-infrared wave bands that are in an urgent need for military aspect. Generally, DF lasers can be divided into two working categories: chained and unchained. The chained DF lasers are with a large structure, simple explosion of working gas and difficult maintenance, though a high power output. However, unchained pulsed DF lasers, available to avoid the disadvantages of explosion and decay during continuous wave operations, have a small volume and are manipulated simply, with high average power and peak power. The research work in this dissertation is about developing a novel kind of pulsed DF laser mainframe and then analyzing the properties of output laser by the developed mainframe. The pulsed DF laser mainly consists of a vacuum system, a gas cyclic cooling system, an optical resonator system, and a main support. The gas cyclic cooling system has the components of fans, heat exchanger, flow passage, and molecular sieve. After changing the structures and positions of the pipelines, the off-centric fans which are special for fast axial flow lasers are successfully applied on DF transverse flow laser. The two units of fans provide the driving force for the gas cyclic flowing by parallel-connected way. In this paper, the flat-concave stable cavity is applied to the optical resonator. Total-reflecting mirror is a spherical mirror while output mirror is a flat mirror. The resonator modulates the directions of optical axes through a multi-orientation structural adjustment. And a convenient fast three-compressing and three-pulling structure is adopted to the angle adjustments of total-reflecting mirror and output mirror. The molecular sieve has the function of absorbing excited species extinctions generated by working process to maintain the stable output of lasers. The finite element method is used to study the static properties of the whole mechanism and then optimize the mechanism to obtain an improvement. After optimized, the mechanism whose maximum deformation is reduced from 2.34mm to 1.67mm has a smaller entire deformation than before. The maximum stress is reduced from 296MPa to 193MPa to decrease the stress concentration phenomena. It can conclude that the strength and stiffness of the whole mechanism meet working requirements. Then, the principle of computational fluid dynamics is employed to numerically analyze the motion states of gas in flow field. The analyses include the pressure loss in gas flowing process, flowing velocities of discharged areas, and uniform distribution, and so on. Furthermore, the flow passage is optimized as to an improvement in accordance with its influential factors. After optimized, by a pitot tubes, the measured flowing velocity of discharged areas is up to 16.3m/s. The maximum non-uniformity of longitudinal flowing velocity distribution is up to 7.1% while the lateral 4.3%. Both of the tested results can satisfy the working requirements. Experiments of single pulse and repetition discharging are carried out with the developed pulsed DF laser mainframe. From experimental results, in the working pressure of 8.1KPa, when the proportion between gases is SF6:D2=8:1, output energy of single pulsed laser reaches to 3.6J. Also, when the repeat frequency is 50Hz, the average power reaches to 150W.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/41459
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	邵明振. 放电引发非链式脉冲DF激光器主机结构研究[D]. 中国科学院大学,2014.

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