【作者】 贾勇；

【导师】 高云国；

【作者基本信息】 中国科学院研究生院(长春光学精密机械与物理研究所) ， 机械制造及其自动化， 2014， 博士

【摘要】 激光发射系统在目标跟踪以及激光通信等领域应用广泛，但工作环境的热冲击以及探测目标的远近变化等问题对系统的功能实现提出了新的挑战。在此背景下，着眼于激光发射系统的远场性能，本文分别对光机热耦合分析和优化技术，以及激光扩束系统的光学变倍设计方法进行了一些新的探索。首先，光学系统对激光束的变换、像差理论以及光束传播算法和光束质量评价等内容是研究激光束远场性能的理论工具，是进行激光光学设计的数学基础。本文首先对这些内容进行了归纳和总结，对比了几种典型波像差对激光远场指标的影响，得到了对光机设计和变倍方法的一些启示；然后在此基础上建立了扩束系统的失调模型，并借助齐次变换，将失调模型进行了一般性推广。其次，开发了一套新颖的光机热耦合分析和光机优化技术路线。通过二次开发的方式，将扩束系统的失调模型融合到了有限元分析之中，绕过了传统光机热集成分析的复杂流程，并能够将各种成熟的结构优化算法收为己用，真正实现了以光学指标最优为目标的光机结构优化。以扩束系统大支撑架为例，相对于优化前的热冲击分析，成功将±50℃范围内的系统波像差降低了近3/4，出射光束的远场指标基本恢复为理想状态，优化完成的支撑结构仅采用了一种传统材料HT200，无复合材料、无柔性环节、加工工艺性良好。最后，提出了一种新型的切换变倍扩束方案，并专门为之设计了一套可靠的装调流程。借助几何光学和物理光学相结合的优化方法，以共用一片主镜、切换工作次镜的方式，实现了离轴反射式扩束系统的×1.5和×1.8两档变倍，两档出射光束的中心位置和光束指向几乎完全相同，仿真实验和装调实验都验证了设计结果的正确性，这为激光变倍发射系统的研发应用奠定了基础。更多还原

【Abstract】 Laser beam launching systems are widely used in the areas of target trackingand laser communication in which a variety of new challenges, such as workingtemperature and target’s distance variations, are arising. Based on these problems,aiming at improving the beam’s far field performance, some explorations on theoptomechanical analysis and laser beam expander design methods were carried outin this dissertation.Firstly, rules of optical system transforming the laser beams, aberration theory,and beam propagation algorithms et al, are mathematical tools to evaluate thebeam’s far field performance. Thereby, these contents were summarized initially,assisting in analyzing the impact of several typical wavefront aberrations on beams.And then, the misalignment model was established and subsequently furthergeneralized by means of homogeneous transformation.Secondly, a novel approach for thermal-optomechanical coupling analysis wasproposed. By using secondary development techniques, optical system’smisalignment model was integrated into the finite element analysis within whichthere are a number of sophisticated structural optimization algorithms. Differentfrom the traditional integrated analysis, this method made the purpose of effectivelyoptimizing the mechanical structure for an optimally optical performance feasible.As an example, the wavefront aberration of a beam expander was successfully reduced nearly by3/4times compared with bracing structure not optimized within arange of±50℃, that is, it achieved an almost ideally emitting beam. And theoptimized bracing structure was easily fabricated with one kind of conventionalmaterial, HT200, and without flexible elements and composite materials.Finally, a creative switching zoom scheme for laser beam expanders, as well asits special alignment program, was proposed. Through combining the geometricaland physical optics in optical optimization, in the form of sharing one main mirrorand switching different secondary working mirrors, a zoom off-axis reflective beamexpander was designed. This expander is available to switch its expanded ratio from1.5to1.8, keeping the two emitting beams’ central positions and directions as thesame. The simulation and adjustment experiment results both validated the designand set the foundation for the applications of laser zoom launching systems.更多还原