基于MEMS技术的微自适应光学系统的建模及关键技术研究

【作者】 饶伏波；

【导师】 姜澄宇；

【作者基本信息】 西北工业大学 ， 机械制造及其自动化， 2005， 硕士

【摘要】 随着自适应光学技术的发展及应用的推广,传统的大型自适应光学系统已不能较好地满足航空、航天、机载激光武器、卫星遥感等领域的要求。微型化、集成化已成为自适应光学系统的发展方向,同时也是现代医学高分辨率成像、激光通讯等领域的一项迫切需求。而MEMS技术的出现与发展使自适应光学系统的微型化、集成化甚至单片集成(SOC)成为可能。基于MEMS技术的微自适应光学系统成为各国的研究重点。因此,开展微自适应光学系统建模及其关键技术研究具有重要的研究意义和应用前景。 本文针对基于MEMS技术的微型自适应光学系统的波前扰动理论、波前传感技术、波前重构理论以及微变形镜波前校正进行了建模与仿真,并对MEMS微变形镜的设计等一系列关键技术进行了研究,论文主要研究内容包括: 1.研究了柯尔莫哥洛夫大气湍流统计模型,以及在小扰动近似下柯尔莫哥洛夫湍流大气对波前相位的扰动大小,得出了湍流层影响的线性叠加特性。 2.研究与比较了三种波前传感技术以及两种波前重构理论,确定了Shack-Hartmann波前传感技术和基于Zemike多项式的模式法重构理论适合用于微自适应光学系统的波前传感与波前重构,建立了微自适应光学系统理论模型,并实现了微自适应光学系统波前传感、波前重构以及波前校正的仿真,分析了仿真结果。 3.针对基于MEMS技术的分立式微变形镜波长校正范围较窄的问题,设计了两种新型可变刚度的弹性梁,分析了其对分立式微变形镜的波长校正范围的影响。 4.采用表面加工工艺对四种形式的分立式微变形镜进行了工艺和版图设计。 本文的仿真与研究结果表明,应用分立式微变形镜可以明显校正畸变波前,显著提高Strehl比;应用两种新型的弹性梁均可显著提高分立式微变形镜的波长校正范围。更多还原

【Abstract】 With the rapid development and the wide application of adaptive optics technology, the traditional large adaptive optics system can no longer meet the need in the fields such as aviation and aerospace, laser weapons, medical high-resolution imaging and laser communication systems. Some adaptive optics systems with low cost, low volume and high performance are expected. The advent of MEMS technology offers the possibility of making that kind of adaptive optic system. With the MEMS technology, the functions of wavefront sensing, reconstruction and correction can even be preformed on a single chip. So, the micro-mechanical adaptive optic system is being more and more promising. In this thesis, the model of a micro-mechanical adaptive optic system was established and some simulations were made. In addition, several key technologies about the micromirror design were explored.Firstly, the Kolmogorov statistical model of the atmospheric turbulence and the wavefront distortion by effects of turbulence were studied. The conclusion was drawn that the wavefront distortion effected by several turbulences could multiply linearly.Secondly, three kinds of wavefront sensing technologies and two kinds of wavefront reconstruction theories were studied and compared, then the Shack-Hartmann wavefront sensing technology and the Zernike-based modal wavefront reconstruction method were selected for the modeling of the micro-mechanical adaptive optics system. After that, the wavefront sensing, reconstruction and correction of the system were simulated and the results were analyzed.Thirdly, two kinds of flexure beams with changeable elastic stiffness were designed and their applications in extending the valid stroke of the micromirror with the electrostatic parallel-plate actuators were analyzed.Finally, the corresponding microfabrication process and layout of four kinds of segmented deformable micromirrors were designed.The results of the simulation and research indicate that the segmented deformable micromirror can effectively correct the distorted wavefront and can increase the Strehl ratio obviously. And by using any kind of these two springs, the valid stroke of the micromirror can be extended definitely.更多还原