飞秒激光与铬膜的相互作用研究
文献类型：学位论文
| 作者 | 谢金 |
| 学位类别 | 博士 |
| 答辩日期 | 2009 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 周常河 |
| 关键词 | 飞秒激光 金属铬膜 衍射光学现象 PDMS 微波纹 |
| 其他题名 | Research on the interaction between the femtosecond laser and Cr film |
| 中文摘要 | 飞秒激光具有极高的峰值强度和极短的脉冲持续时间，它与物质相互作用时，能够以极快的速度将其全部能量注入到很小的作用区域，瞬间内的高能量密度沉积将使电子的吸收和运动方式发生变化，使飞秒激光加工成为具有超高精度、超高空间分辨率和超广泛性的非热熔处理过程。为了提高飞秒激光微加工的精度，以及应用飞秒激光制作出更多的微小器件，飞秒激光和物质的相互作用在实验和理论方面均得到了广泛的研究。本文在飞秒激光和物质的相互作用这个领域中主要研究了飞秒激光同金属铬膜，以及飞秒激光同聚二甲基硅氧烷(PDMS)的相互作用。在研究过程中，发现并解释了两种新的实验现象。主要内容包括以下几个方面： 选择在激光微加工中常用的以玻璃为基底的金属铬膜为加工对象，研究了飞秒激光同金属铬膜的相互作用，发现了可逆的衍射光学现象。当透射探测光通过100nm金属铬膜时形成了可逆的暗中心衍射现象，在探测光的反射光中形成了可逆的亮中心衍射现象，这两种现象都是由泵浦飞秒激光所引起的。为了解释飞秒激光同金属铬膜的相互作用机制，提出了一种衍射光学解释，这种解释认为：存在于透射探测光中的，可逆的暗中心衍射是由可逆的金属铬膜的位相改变所引起的，而这种可逆的铬膜的位相的改变是由飞秒激光所激发的。一种二元位相板衍射光学模型被用来解释在透射探测光中的这种暗中心到亮中心的可逆改变。本文通过对容易探测的衍射光学现象的观察，分析了由飞秒激光所引起的可逆的铬膜的位相变化，这种可逆的铬膜的位相变化是较难以其它方式探测的。这部分内容有助于大家对飞秒激光和金属相互作用机制的理解。 具有有机硅树脂材料诸多优点的PDMS在实验研究和工业界中有着广泛应用，特别是在紫外压印技术中，PDMS是不可多得的好材料。在紫外压印技术中，如果能直接把微小图形制作到PDMS材料表面，那就不再需要母板了，这样既简化了工艺，又节约了制作母版的成本。本文研究了飞秒激光同PDMS的相互作用，发现了飞秒激光在加工PDMS薄膜表面时所形成的微波纹的现象。通过飞秒激光光斑在PDMS薄膜表面的移动，在加工出的直线两侧，产生了微波纹。飞秒激光光斑在材料表面的移动和由飞秒激光所引起的材料的熔化被认为是产生微波纹的原因。微波纹的形状同飞秒激光的功率和偏振态有关。一种船头波的观点被用来解释这种实验现象。在PDMS表面所形成微波纹的物理机制和在金属和硅上形成的微波纹的物理机制不同。本文中所发现的微波纹应该引起相关研究领域的研究人员的足够重视，它对我们理解飞秒激光同聚合物的相互作用是有意义的。 在做光学实验时，通常需要自行搭建光路。当需要搭建一个复杂的光路时，进行系统的光学设计往往是必需的。本文完成了一种新型三维内窥镜的光学系统设计工作，这种新型内窥镜能得到测量目标的三维面形分布，提供测量目标的深度信息。这部分的研究内容如下： 现在常用的内窥镜系统只能得到被测物体的二维的像，而丢失了被测物体的三维面形分布和深度信息。本文研究了一种将傅立叶变换轮廓术（FTP）应用于内窥测量的装置。这种基于振幅型光栅投影的三维内窥装置解决了扫描部件复杂、控制精度要求高、测量时间长等技术问题。这种测量装置只需要一帧形变的光栅投影图像就可以计算出物体的三维面形分布。它能够得到内窥对象的三维形貌信息，测量速度快，实施方法简单，有较高的测量精度。因为在这种新型的三维内窥镜中加入了光栅，所以在设计它的光学系统时要考虑光栅的衍射效应。本文在这部分具体介绍了光学系统设计的过程和步骤，并应用光学设计软件Zemax设计出了适用于这种新型三维内窥镜的照明微透镜组和成像微透镜组。本文的光学设计工作对这种新型三维内窥镜走向实际应用具有较大的推动作用。 |
| 英文摘要 | The peak intensity of the femtosecond laser is very high and the pulse width of the femtosecond laser is very short. When the femtosecond laser interacts on the material, all of the energies are quickly injected into a very small zone and instantly high energy density changes the moving and absorbing styles of electrons. These characteristics are non-hot-melt processing course with superhigh precision, space resolution and extensity. In order to develop the precise processing and fabricate more micro-devices, the interactions between the femtosecond laser and materials are widely studied in both experimental and theoretical fields. The main content of the dissertation is about the researches on the interaction between the femtosecond laser and Cr film and PDMS. In this dissertation, two new experimental phenomena are found and explained. The main content is as follows: When we utilized femtosecond laser to micromachine Cr film with a thickness of 100nm, we found reversible dark-center diffraction of the transmitted probe beam passing through the chromium film and reversible bright-center diffraction of the reflected probe beam from the chromium film, which are induced by the pump femtosecond laser. The dark-center diffraction of the transmitted probe beam and the bright-center diffraction of the reflected probe beam appear and disappear with and without the pump beam. A view of diffractive optics with binary phase plate is put forward, which explains the reversible dark-center diffractive optical phenomenon. The pre-ablated hole on the metal film can be regarded as a uniform light filed without phase modulation, the surrounding circular part around the pre-ablated hole can be regarded as “phase modulated”. Therefore, this diffractive optic view might be helpful for us to understand the phase change of the metal film introduced by the femtosecond laser pulse. The microripple is found in the processing of the PDMS by removing the femtosecond laser. There is an acute angle between the microripple and the ablated line. The movement of the laser spot on the surface of the PDMS and the melting of the material induced by femtosecond laser are able to produce microripples. The shape of the microripple is related to the power and the polarization of the laser. A wave explanation is put forward to elucidate the experimental phenomenon. The physical mechanics of the microripples on PDMS surface is different from the microripples formed on metals and Si. Consequently, the finding of the microripple should be interesting for us to understand the interaction between femtosecond laser and polymer. When building up complexly experimental light path, we should engage in optical design. The design of optical system is studied in the dissertation. The content of this part is as follows: Now, normal endoscope can only receive the 2D image and lose the 3D information of an object. In the dissertation, I designed the optical system of a 3-D endoscope measure system, which bases on FTP and grating projection technology. The new-style endoscope can get the 3D information of an object. Because there is a grating in the new-style endoscope, the diffraction of the grating should be concerned in the design of the optical system. Zemax is used to design the illuminating and imaging systems of the 3D endoscope. The optical design is useful to realize the practical application of the 3D endoscope. |
| 语种 | 中文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15262]  |
| 专题 | 上海光学精密机械研究所_学位论文 |
| 推荐引用方式 GB/T 7714 | 谢金. 飞秒激光与铬膜的相互作用研究[D]. 中国科学院上海光学精密机械研究所. 2009. |
入库方式： OAI收割
来源：上海光学精密机械研究所
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