熔石英光学元件加工亚表面缺陷检测及抑制技术研究进展

Progress in Detection and Suppression Techniques for Processing-induced Sub-surface Defects of Fused Silica Optical Elements

熔石英材料因具有硬度大、热膨胀系数低、透射光谱范围广等良好的机械性能和热学、光学特性,广泛应用于国防、航天等领域中关键光学元件的制造。作为一种典型的硬脆材料,在传统的研磨抛光加工中,不可避免地会引入亚表面层的微裂纹、划痕等结构性缺陷,这些缺陷会严重降低熔石英元件在高功率激光使用环境下的激光损伤阈值,并影响其在高冲击载荷使用环境下的抗断裂损伤能力。从硬脆材料的磨削机理出发,对熔石英光学元件亚表面缺陷的产生机制、亚表面缺陷的检测技术、熔石英亚表面缺陷抑制技术的研究现状进行综述,重点对比针对加工亚表面缺陷的有损检测和无损检测技术的优缺点,探讨多种先进表面加工技术在抑制熔石英光学元件亚表面缺陷中的应用。希望为优化大口径、高精度、高质量熔石英光学元件加工工艺,并提升其在高功率激光、高冲击载荷等极端服役环境下使用性能、延缓其使用寿命提供有益参考。

Since fused silica material possesses good mechanical properties, thermal and optical properties, such as high hardness, low coefficient of thermal expansion, and wide transmission spectrum, it is widely applied in manufacturing key optical components in the fields of national defense and aerospace. As a typical hard and brittle material, subsurface micro-cracks and scratches would be inevitably introduced in the traditional grinding and polishing process, which will seriously reduce the laser damage threshold of components employed in high-power laser environment and also affect the anti-fracture damage ability under extremely high impact load. Starting from the grinding mechanism of hard and brittle materials, this paper reviews the generation mechanism of sub-surface defects in fused silica optical components, the detection technology of sub-surface defects, and the suppression techniques of sub-surface defects in fused silica. The advantages and disadvantages of destructive and non-destructive detection techniques for processing-induced sub-surface defects are compared and the application of a variety of advanced surface processing techniques in suppressing sub-surface defects of fused silica optical components is discussed. This work is helpful in providing useful guidance for optimizing the processing technique of fused silica optical components with large-aperture, high-precision and high-quality, and improving their performance and service life when used in the extreme service environments such as extremely high power laser and high impact load.