基于激光直写系统的衍射光栅制备
文献类型：学位论文
| 作者 | 王津 |
| 文献子类 | 博士 |
| 导师 | 周常河 |
| 关键词 | 激光直写系统 direct laser writing system 衍射光栅 diffraction gratings 旋转达曼光栅技术 rotating Dammann grating technology |
| 其他题名 | The Fabrication of Diffraction Gratings Based on the Direct Laser Writing System |
| 英文摘要 | 衍射光栅作为微纳光学器件中的关键色散元器件，具有分束、偏振、相位匹配等特性，广泛应用于激光器、激光调制、激光计量学、激光测量等诸多领域。与此同时，大尺寸光栅在天文、光谱仪、引力波探测等领域也有着极其重要的作用。另外，大尺寸光栅是脉冲压缩的重要光学元件，造价十分昂贵，而且西方发达国家对我们实施禁运，我国激光工程所需的大型光栅只能依靠自主开发。传统光栅制备技术，例如机械刻划法、全息法等在制备大尺寸衍射光栅上都有所欠缺，以往的光栅制备技术已经很难满足激光工程的要求，激光直写技术成为最有可能解决此难题的备选技术方案。激光直写技术自20世纪80年代首次提出，便得到了广泛的关注。激光直写技术是无掩膜光刻技术的一种，通过激光束在涂有光刻胶的基片上扫描得到所需要的图形。因此，我们提出了基于旋转达曼光栅的激光直写技术，并在以往技术基础上，搭建了大行程的激光直写系统。本博士论文是在总结前人工作的基础上，对该系统的搭建及关键技术进行分析研究，通过制备相关衍射光栅元件对该系统的性能进行验证。本博士论文将围绕基于激光直写系统的衍射光栅加工制备这一主旨进行展开，主要围绕以下几个方面开展相关的研究工作： 1.设计并讨论分析用于制备衍射光学元件的激光直写系统的整体设计方案以及其每个子模块。我们将整个系统分为几个部分，首先是分析搭建光路系统，介绍直写光路的原理及几个关键性元部件的选型，重点分析介绍基于像散法的自聚焦光路的原理，引入FES误差信号曲线，设计自聚焦光路系统，并在此基础之上提出差动自聚焦技术，搭建设计差动自聚焦光路，对其进行模拟仿真，对差动自聚焦的性能进行分析说明；其次是运动系统的搭建，比较分析了几种不同形式的导轨，最终采用气浮导轨的移动平台，并对选取的移动平台进行了选型说明分析；再次，在整个光路系统、运动系统搭建完成的基础上，对整个系统进行整合，通过不同的机械设计方案及隔振平台的选取，使得整个系统保持最优的性能及稳定性；最后是对整个系统的硬件和软件系统进行分析说明，整个系统是以计算机为核心，由计算机连接各个系统，发出操控指令，详细说明了自聚焦操作软件及气浮移动平台的操作软件。 2.将达曼光栅引入到激光直写系统。达曼光栅是一种能够产生一系列均匀点阵的衍射光学元件，能够在直写系统中作为分束元件，可以一次性直写多条栅线。我们首先介绍达曼光栅原理和达曼光栅的理论设计方法，并且根据理论设计了亚波长达曼光栅。在达曼光栅应用方面，介绍了旋转一维、二维达曼光栅分束并行直写技术，推导出刻写周期与旋转角度之间的关系式。为了进一步提高刻写的精度，减小随机误差，消除拼接问题，我们提出了并行重复直写技术。 3.对系统的几个关键部分进行了优化调试。主要针对移动平台控制问题，优化PID参数，观察PID参数改变后直写条纹效果，选取合适的PID参数使整个系统达到最优效果；通过架设激光干涉仪观测平台振动情况，针对移动平台的气路问题，增加露点仪控制，保证气路稳定；由于像差、色差、安装误差等原因，造成红光自聚焦光路不能完全直接反应蓝光的焦点，需要调节FES参数值，手动校准蓝光焦点，满足直写要求。 4.在实验方面，首先介绍衍射光学元件的基本制备工艺流程，然后介绍光刻胶的相关性能、刻蚀的工艺技术。重点是对已搭建好的基于达曼光栅的大尺寸激光直写系统进行了性能验证与测试。主要表现为制备了大尺寸衍射光栅掩膜版，以及利用简化模式方法设计了TE偏振下 800 nm 高效率 1×3反射式三角光栅分束器，并且通过本并行刻写系统进行制作，对该光栅分束器进行光谱效率测试。还制备了大发散角的二维光栅，实验结果进一步证实了该直写系统的直写性能。 本文构建了整个系统的理论模型，并在理论模型的基础上搭建了实体衍射光学元件的激光直写系统，制备了不同类型的衍射光栅元件。该直写系统具有拓展性、灵活性、便利性的优点，能够符合制备衍射光栅的要求。; Diffraction gratings are the key components in optical devices, which have the characters of beam splitting, polarization, phase matching, and so on. They are widely used in the fields of laser source, laser modulation, laser metrology, laser measurement. Meanwhile, large-sized gratings play an important role in the fields of astronomy, spectrometer and gravitational wave detection. However, the price of large-sized pulse compression gratings (PCG) is quite high, furthermore, the western developed countries have imposed an embargo on us. Hence, large-sized pulse compression gratings expected for laser engineering in China can only depend on our independent development. Traditional grating fabrication technologies, such as holographic grating and ruling grating, have difficulties in fabricating large-sized gratings. The former technologies of making gratings have been already difficult to meet the requirements of laser engineering. Direct laser writing (DLW) technology has become the most promising alternative technology to solve this problem. The direct laser writing technology was proposed in 1980s, and it has received much attention since then. The direct laser writing lithography technology is a kind of maskless lithography technology, which can get the needed structure by laser scanning on the substrates with photoresist. Therefore, we have proposed a direct laser writing technology based on rotating Dammann grating. And we have set a direct laser writing system of diffraction gratings on the basis of former research foundation. On the basis of summarizing the previous work, this dissertation analyzes the construction of the system and the key technologies, and verifies the performance of this system by the fabrication of diffraction grating elements. This doctoral dissertation, on the aim of developing a direct laser writing system for diffraction gratings, mainly focuses on the following aspects: 1.Design and analyze the overall design scheme and each submodule of the direct laser writing system of diffraction gratings. We divide the system into several parts. Firstly, design and set up the optical system. This doctoral dissertation introduces the principle of the writing optical system and several key components, and lays special stress on analysis of the principle of self-focusing system based on optical astigmatic method. We introduce the error signal curve, design the self-focusing optical system, and propose a differential auto focusing technique. On the basis of it, the differential self-focusing optical system is designed and built. We have carried on the simulation of differential self-focusing and the analysis of performance. Secondly, set up the motion system. We compare and analyze several different types of sliders, and choose the air-bearing sliders finally. Then, on the basis of building the optical system and motion system, integrate the whole system by choosing mechanical design and isolation platform which make the whole system maintain optimal performance and stability. Last, the hardware and software systems of the whole system are analyzed. The whole system takes computer for centralization. Each part is connected to the computer and operated by the computer. The operation software of self-auto-focusing and operation software of air floating platform are described in detail. 2.The Dammam grating is introduced into the direct laser writing system. Dammann grating is a kind of grating which can create a finite array of uniform intensity spots. It can be used as a beam splitter in direct laser writing system, which can write several lines at the same time. The theory of Dammam grating and the theoretical design method of Dammam grating are described. According to the theory, the subwavelength Dammann gratings are designed. In the aspect of application of Dammam grating, the technology of rotating 1D and 2D Dammann gratings is depicted. The expressions between rotation angle and period are derived in this dissertation. In addition, to improve the writing accuracy and decrease the random errors, another method of repeated-parallel directed laser writing based on Dammann grating is introduced. 3.Several key parts of the system are optimized. Mainly aiming at the control problem of moving platform, optimize the PID parameters. The optimized PID parameters make the whole system achieve the best performance by observing the grating lines. The vibration of the platform because of the gas path is observed by the laser interferometer. In order to solve the problem of the gas path, add the dew-point hygrometer to the system to ensure the stability of gas path. Due to several errors, the position of focal point of the blue light is different from the red laser. We need calibrate and correct the value of FES so that the blue laser is focused on the focal point. 4.In the aspects of experiments, the basic process flow of diffractive optical elements is described first. And then the related properties of photoresist and the technology of etching process are introduced. Verify and test the performance of this direct laser writing system based on Dammann grating emphatically. The large-sized diffraction grating mask is fabricated by laser writing. And a highly efficient 1×3 grating splitter is optimally designed and fabricated, which is at the wavelength of 800 nm under TE polarization under normal incidence. For further understanding, the simplified modal method is applied to explain this diffraction process. The spectral efficiency of the grating splitter is tested, and the all experimental results verify the feasibility of the direct laser writing system of large-sized diffraction optical elements. This doctoral dissertation describes a theoretical model of the whole system, and we set up the direct laser writing system on the basis of the theoretical model. The different types of diffraction gratings have been fabricated based on the system. This system has advantages of flexibility, expansibility and convenience. The direct laser writing system can meet the requirements of fabricating of large-sized diffraction gratings. |
| 学科主题 | 光学工程 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/30973]  |
| 专题 | 中国科学院上海光学精密机械研究所 |
| 作者单位 | 中国科学院上海光学精密机械研究所 |
| 推荐引用方式 GB/T 7714 | 王津. 基于激光直写系统的衍射光栅制备[D]. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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