Abstract In the high frequency laser system, the internal defects of optics will affect their damage threshold and downstream modulation, and even lead to subsequent surface damage. In order to efficiently and reliably evaluate the internal defects in optics, an automatic evaluation method of scattering defects in optics is proposed, and the corresponding three-dimensional (3D) precision measurement system is established. The detection principle, image acquisition, image processing and bulk defects (BDs) information extraction methods of the system are studied. Based on a 3D dark-field microscopic imaging (DFMI) technology, samples are scanned with multi-dimensional motion devices. Meanwhile, the scattered beam from the BD was collected by a detector, and finally combined with the digital image processing technology, the acquired images are processed in real time. Through real-time focusing and improved 3D reconstruction algorithm, the images with full aperture BD features are obtained, and the position and size information of defects are extracted. The system has detected the BD inside the fused silica samples. The results show that our system can distinguish the 612.7 lp/mm. Furthermore, the 3D distributions of the BD were also reconstructed.

中文翻译：

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光学大块缺陷自动评估系统

摘要 在高频激光系统中，光学器件内部缺陷会影响其损伤阈值和下游调制，甚至导致后续的表面损伤。为了高效、可靠地评价光学内部缺陷，提出了一种光学散射缺陷自动评价方法，并建立了相应的三维（3D）精密测量系统。研究了系统的检测原理、图像采集、图像处理和块体缺陷(BDs)信息提取方法。基于 3D 暗场显微成像 (DFMI) 技术，使用多维运动设备扫描样品。同时，来自BD的散射光束被探测器收集，最后结合数字图像处理技术，实时处理获取的图像。通过实时对焦和改进的3D重建算法，获得具有全孔径BD特征的图像，并提取缺陷的位置和尺寸信息。系统已检测到熔融石英样品中的 BD。结果表明，我们的系统可以区分 612.7 lp/mm。此外，还重建了 BD 的 3D 分布。