Abstract: 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.

Key words: fused silica optical elemen, subsurface defects, grinding mechanism, detection technology, suppression of defects