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题名	多波段高功率激光合束技术及热效应研究
作者	孙毅
学位类别	博士
答辩日期	2015-05
授予单位	中国科学院大学
导师	高云国
关键词	激光发射系统 激光合束 光机热耦合分析 热畸变 远场光束质量
其他题名	Research on Multi-wavelength Laser Beam Combination Technology and thermal effect
学位专业	机械制造及其自动化
中文摘要	高功率大口径激光发射系统是各国在工业及军事等领域研究的热点前沿问题。为了满足光电设备的使用需求，本文提出一种多波段高功率激光合束发射方法，集跟踪发射于一个系统，各波段激光进行非相干合束后共口径发射，系统体积小，结构简单，机动性能良好，可适应不同环境下的使用要求，是一种新型的激光发射方法。在高功率激光系统中，光学元件产生的热效应将导致输出激光光束质量下降，利用有限元软件和Matlab软件作为工具，采用光机热一体化分析流程，围绕合束系统激光热效应、环境温度热冲击和远场光束质量评价等方面展开了研究 在合束系统设计阶段，首先对不同的非相干合束方法进行研究，确定了采用波段合束方法对三个波段激光进行合束，合束镜的基底材料选择优良的红外光学材料ZnSe。其次推导了激光远场重合效率公式以及激光远场覆盖目标公式，并利用Zemax软件结合重合效率公式对合束光路进行了仿真，对合束系统关键参数的选择提供了支持。最后，介绍了与合束系统配套的光路监测和校正系统，并对合束镜的几何参数和合束系统机械机构进行了设计分析。 参与合束的红外材料ZnSe属于对热较敏感材料，ZnSe材料合束镜不仅有面型畸变同时还存在温差产生的折射率梯度变化，所以利用光机热一体化分析方法对合束镜和合束系统进行了热光学分析。首先建立了不同工况下合束镜的温升和结构分析模型，利用有限元法计算了在不同边界条件和不同工况下的温度场分布以及热变形，计算了对流换热系数和镜架热传导对计算结果的影响，并对不同光斑尺寸和不同合束镜厚度对热畸变产生的影响进行了仿真计算，总结了合束镜的热畸变规律。其次对实际应用中的合束系统进行了热光学分析，对激光偏置造成的波前畸变进行了具体分析，计算了在激光运行90s时间内的各波段激光波前畸变，并对不同环境温度对激光远场光束质量的影响进行了仿真计算。最后，提出了针对合束系统的温控措施，该方法可以在激光器运行间歇将沉积的热量带走。 建立了激光辐照热效应实验平台和激光远场功率测试平台，对合束镜的激光辐照热效应进行测试。结果显示，热效应实验得到的结果与仿真计算的结果基本吻合。针对高功率激光系统难以测试的问题，可以利用仿真计算并结合低功率激光作为替代光源对高功率激光热效应进行验证。搭建激光远场实验平台，利用热成像仪-功率计的方法测试激光系统热效应对远场激光的影响，可以看到热效应造成了远场激光功率下降，但测试数据波动较大，仍需进一步消除测量误差。
英文摘要	High power and large aperture laser transmitter system is the hot and frontier research problem in the industry and military field. In order to meet the usage requirements of optoelectric apparatus, this paper proposes a laser beam combination transmitter method with multi-band and high power laser. It is a system combines with tracking and emission. After the laser on each band has been incoherent beam combination, the transmitter system will emission in the way of co-aperture . This system is a new laser transmitter method which has minimized weight, simple structure and well maneuvering performance and it can adapt to general operational requirements in different environment. In the high power laser system, the thermal effect produced by optical elements will lead to a quality reduction of the laser beam. In this paper, it takes the finite element software and Matlab software as tools, and uses the thermal/structural/optical integrated method for researching the aspects on beam combination system, laser thermal effect, environmental temperature thermal effect, and beam quality in the far field, etc. In the stage of beam combination design, firstly it studies different kind of incoherent beam combination methods, and then determines to take the way of band beam combination for solving all three band laser beam combination. The substrate of beam combination mirror will choose well infrared optical material ZnSe. Secondly, we derive the combination formula for laser and the formula for covering the object in far field. It uses Zemax software to simulate beam combination optical path combined with the accuracy formulas of beam combination, and offers support for selecting the key parameter of beam combination accordingly. Finally, it introduces optical path monitoring and correction system supporting with beam combination system. And it makes design analysis on the geometrical parameter of beam combination mirror and the mechanism of beam combination system. The ZnSe infrared material is sensitive to heat. The beam combination mirror with ZnSe material not only has surface distortion, but also has refractive index change due to the temperature difference. So this paper takes advantage of Thermal/structural/optical integrated method to make thermal-optical analysis for beam combination mirror and beam combination system. Firstly it builds the temperature rise and structural analysis model for beam combination mirror in different load cases. On this condition, it calculates the temperature distribution and surface deformation in different boundary conditions and load cases using the finite element software. The effects of convective heat transfer coefficient and frame heat conduction on numerical accuracy are studied, and the effects of different beam size and different beam combination mirror thickness on the thermal distortion are also simulated. Thus in this paper, it summarizes the thermal distortion rule of beam combination mirror. Secondly, it makes a thermal-optical analysis about beam combination system in practical application. It makes a concrete analysis about wavefront distortion due to the laser bias. It also calcculates the laser wavefront distortion in each band within 90s of laser running, and the effect of temperature on far field laser beam quality in different environments is calculated. Finally, it proposes a temperature control method for beam combination. It will take the heat accumulation away in the intermissions of laser running. At last, it establishes the experimental platform of laser thermal effect and test platform of laser power in the far field, Firstly, the platforms test the laser irradiation thermal effect of beam combination mirror. The results shows that the results of thermal effect experiment are in good accordance with the results of simulation calculation. On the issues of high power laser systems are hard to test, it can be verified by using alternative light sources with low power laser and simulating calculated method. The experimental platform of far field laser makes use of the thermal imager-power meter to test the impact of laser system thermal effect on the far field laser, the thermal effect caused the decreasing of the far field laser power, but due to the data fluctuation of the test, it is also need further reduce the error.
公开日期	2015-12-24
内容类型	学位论文
源URL	[http://ir.ciomp.ac.cn/handle/181722/48898]
专题	长春光学精密机械与物理研究所_中科院长春光机所知识产出
推荐引用方式 GB/T 7714	孙毅. 多波段高功率激光合束技术及热效应研究[D]. 中国科学院大学. 2015.

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