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摘要点衍射干涉仪利用极小孔径衍射形成近乎理想的球面波作为测试参考波前。这种干涉仪具有极高的检测精度，可以为大口径激光束的瞬态波前检测提供技术支持。为了实现对激光器出射波前质量的检测，点衍射干涉仪需要具备较好的衍射参考波前质量与干涉图对比度。因此其关键器件的性能与参数的设计是一项重要的工作。本论文基于传统点衍射干涉仪，设计并搭建了准直波前干涉测试系统，对系统中关键器件的性能与核心参数进行了研究。主要研究内容如下：21362
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1. 建立了小孔衍射数学模型，确立入射光场、小孔与衍射波前误差的关系。对小孔直径与形状偏差、入射波前像差、横向与轴向调整误差进行了仿真研究。结果表明，小孔形状偏差对波前质量影响较小，横向对准偏差与象散是影响参考波前质量的主要因素，对于波长为532nm的激光器而言，若要保证对艾里斑中央亮斑范围内的横向偏离能满足系统的精度要求，小孔直径不能超过7um。
2. 研究了点衍射干涉仪中参考光束和测试光束的光强匹配问题。对比分析了小孔直径不同、小孔横向离焦、入射波前包含像差时的光强变化。仿真结果表明小孔直径越小，衍射光强越弱。对于给定小孔直径与透过率，轴向离焦可以较好的调整干涉图的对比度，横向离焦能在一定程度上提高对比度。点衍射板透过率设计为其无横向离焦时最佳透过率的1/5较为合理。利用透镜的傅里叶变换性质，将点衍射干涉系统看作4f系统进行建模，通过仿真验证了离焦对干涉图对比度的调整作用。
3. 实验测量了小孔衍射的出射波前。构建了直径10um针孔衍射波前检测实验系统，将检测结果与仿真对比，二者的PV值偏差0.025 ，RMS偏差0.052 。构建了点衍射干涉仪测量实验系统，验证了给定透射率，不同直径小孔的点衍射板，可通过调整离焦获取对比度较好的干涉图。利用傅里叶变换法从干涉图中恢复待测波面，结果与SID4波前探测器的测量结果基本吻合，验证了点衍射干涉仪的可行性。
关键词：点衍射干涉仪，波前检测，参考波前，衍射光强，标量衍射
毕业论文设计说明书（论文）外文摘要
Title The Emisson Wavefront Simulation Analysis of Point Diffraction Interferometer
Abstract
Point diffraction interferometer use small aperture to diffract nearly ideal spherical wave as the reference wavefront for test. This interferometer has a very high detection accuracy, which can provide support for the transient wavefront test of the laser beam in large diameter. In order to test the emission wavefront quality of a laser, point diffraction interferometer need to have a good diffracting reference wavefront quality and contrast of the interference pattern. Therefore, the parameters design and performance of its key components is an important job. In this paper, based on the traditional point diffraction interferometer designed and built a collimating wavefront interference test system, and core parameters and the performance of key components of the system were studied. The main contents are as follows:
1. A hole diffraction mathematical mode and the relationship between the incident light field, apertures and diffraction wavefront errors were established. A simulation study was made on the deviation of the hole diameter and shape, the aberrations of incident wavefront, and the error of lateral and axial adjustment. The results showed that the deviation of the hole shape have less influence with the wavefront quality and the lateral misalignment and the astigmatism are the main factors. For a laser with wavelength 532nm, in order to satisfy the accuracy requirements of the system for the range of the bright central of the Airy disk to deviate in lateral, the hole diameter should not exceed 7um.