| 题名 | 高精度非干涉相位检测技术研究 |
| 作者 | 王海燕 |
| 学位类别 | 博士 |
| 答辩日期 | 2015 |
| 授予单位 | 中国科学院上海光学精密机械研究所 |
| 导师 | 刘诚 |
| 关键词 | 相位检测 相干衍射成像 Ptychography 相位恢复 |
| 其他题名 | High-resolution Phase Measurement Technology Based on Coherent Diffractive Imaging |
| 中文摘要 | 高功率激光驱动装置光路复杂，使用了大量的精密光学元件，在加工、安装和运行过程中的很多因素，诸如材料瑕疵、加工工艺、装校应力、温度变化、重力作用等都可能对其性能产生不良影响。光学元件质量上的偏差最终会通过激光束波前的变化而体现出来，引起波前畸变，从而导致高功率激光驱动装置光束质量下降，降低驱动器的运行稳定性与可靠性。只有准确知道波前畸变的大小和畸变发生的位置，才能采用有效的措施进行纠正并提高光束质量，因此对于光学元件面型精密检测对于光束质量控制非常必要。 对于大口径光学元件的检测，目前一般都是利用大口径干涉仪实现，作为经典的相位测量工具，干涉仪具有高精度和高稳定性等系列优点，但由于其对使用环境要求较高，难以在工程现场环境进行测量，同时对于具有复杂面形的光学元件，由于缺少相匹配的参考镜，测量同样难以实现。因此有必要发展出新的测量手段以满足激光驱动器领域对光场相位或者特殊光学元件面形进行测量的需要。 作为新型的相干衍射成像(Coherent Diffractive Imaging)方法，PIE(Ptychography Iterative Engine)是一种利用衍射理论、卷积定理和奈奎斯特抽样定理，从所记录的散射斑强度直接用迭代算法重建被测物体相位分布的非透镜成像技术。该技术不需要高质量的光学元件，因此成像分辨率不受元件质量的影响，理论上能够实现波长量级的分辨率。PIE方算法于2004年由英国谢菲尔德大学教授John Rodenburg提出，具有收敛速度快、抗噪声干扰能力强、成像范围可扩展以及视场不受CCD尺寸的限制等优点。ePIE 是在在PIE基础上发展起来的一种技术，该技术可以实现对照明光和光路中散射介质相位的同时测量。本论文基于PIE技术，针对高功率激光装置中遇到光学元件位相测量方面的问题展开研究，主要研究内容如下： 1，设计出一种非规则口径光学元件位相检测方法，实现对高功率激光驱动装置中用于束匀滑的连续相位板和高重频激光放大器增益介质热畸变的测量。该方法测量尺寸不受探测器尺寸的限制，可检测位相范围大，无需参考光路，同时可测量到高频信息分量。由于采用的是两次测量求相位差的方式进行测量，因此对于光路照明光质量的要求大大降低，而且抗干扰较好，解决了高重频激光放大器因振动和热畸变量大无法被现有测量技术检测的难题。此外，该方法也应用于长焦阵列透镜焦距的测量，大大缩短了测量光路。 2，提出了一种基于旋转照明方式的相位恢复技术，用旋转的照明光场代替传统PIE技术数据记录过程中待测物体上x-y 方向的平移。由于物体的照明光场是按照一个方向旋转，这样就避免了回程误差，而且由于每次照明都含物体同一部分的信息，在迭代过程中收敛速度的有所增加。该方法还节省了测量空间，适用于空间极为有限的环境中相位测量和成像。 3，设计一种多层光学元件损伤测量方案，通过采集一组数据，在不破坏光学元件固有结构的前提下对元件各层分别成像，同时获得元件各层的振幅和相位信息，实现对不同层元件损伤同时检测。 4，对本文提出的相位检测方法展开误差分析，讨论主要影响因素——平移台误差对最终测量结果的影响，证明在实验所使用平移台现有精度下，测量结果可以很好的满足测量要求。 |
| 英文摘要 | High-power solid state laser facility for the inertial confinement fusion (ICF) employs thousands of large optical components including amplifiers, polarizing films, electro-optical switches, lenses, and mirrors. The performance of these elements can be easily influenced by the material nonuniformity, manufacturing error, assembling stress, temperature changes. The high requirements of the ICF system on the laser beam wave-front need extremely accurate techniques for the laser beam sensing and the optical component measurement, and the measurements of optical components and laser beam at high precision are always important tasks for researchers of ICF. Hartmann-Shack wave-front sensor is always used for the online wavefront detecting and can realize feed-back controlling, and the interferometry is always used to evaluate the properties of the optical elements. However, both Hartmann-Shack wave-front sensor and the interferometry have limitations. Resolution of Hartmann-Shack wave-front sensor is limited by its sub-aperture and the number of the micro-lenses, and the interferometry needs a standard plate to do such a measurement, and for large aperture elements, the manufacturing of the standard plate is very difficult. As a newly developed CDI (Coherent Diffractive Imaging) method, PIE (Ptychography Iterative Engine) is a lensless imaging technique, which could reconstruct the phase distribution of the object with the theories of diffraction, convolution, and Nyquist sampling. It was firstly proposed by John Rodenburg in 2004，and compared with the other traditional CDI methods, PIE has unique advantages including extendable imaging range, high speed convergence, and strong noise immunization ability. Due to its outstanding advantages in the simple setup, compact structure, and low environmental requirements, a series of studies and experiments based on PIE are carried out in the field of high power laser system for phase measurement. The research results are summarized as follows. 1, A method based on Ptychographical Iterative Engine (PIE) was proposed for the measurement of the complex transmittance of large optical elements which are often used in ICF. The method has The method has excellent anti-noise performance and also be used in the measurement of the thermal distortion caused by the pumping light in higher power laser amplifier, which could not be measured by commonly employed interferometry or Hartmann-Shack sensor. 2, A modified extended-ptychographical-iterative-engine (ePIE) algorithm is proposed to overcome the disadvantages of ePIE technique to reduce the influence of the stage hysteresis or back lash error. The exit wave of a rotatable diffractive object illuminated by plane wave is used as the illumination on the specimen, and the complex transmission functions of the rotatable object and specimen can be reconstructed simultaneously. Compared to the standard x-y scanning PIE algorithm, the proposed algorithm can avoid the influence of the stage hysteresis (or backlash error) completely and accordingly has higher convergence speed and better accuracy. 3, 3D Ptychographical Iterative Engine (PIE) is used in damages detection of elements. By splitting elements into axial sections, the complex transmittance of each slice could be reconstructed simultaneously through iterative calculations with a resolution of 3.7μm. 4, The influence of the translation stages error is analyzed with theoretical derivation and numerical simulation. It is pointed out that error of the final measurement results is affected by the focus of convergent lens, the error of translation stages and the spatial position of the measurement point. |
| 语种 | 中文 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.siom.ac.cn/handle/181231/15917]  |
| 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 | 王海燕. 高精度非干涉相位检测技术研究[D]. 中国科学院上海光学精密机械研究所. 2015. |
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