综述了近五年来为神光装置研制大口径熔石英采样光栅所取得的主要进展。提出了大尺寸采样光栅的化学机械抛光技术, 将全息光刻-离子束刻蚀的430 mm口径采样光栅的采样效率均匀性控制在均方根值低于5%, 满足了采样光栅的设计要求。针对采样光栅的阈值特性, 利用二次离子质谱技术, 定量表征了采样光栅制备过程中引入的污染及其清洗效果, 优化、发展了采样光栅的清洗方法。探索了基于氢氟酸和感应耦合等离子体刻蚀的熔石英基底处理技术, 结合干湿法处理技术来去除熔石英光栅基底的亚表面损伤。为进一步提升采样光栅抗激光辐射损伤特性, 提出将发展大尺寸熔石英采样光栅的氢氟酸处理方法及具有亚波长减反光栅结构的采样光栅的制备方法。

This paper reviews the advances in fabricating large-aperture Beam Sampling Grating (BSG) made of fused silica for Shenguang laser facility. A chemical mechanical polishing process for large-aperture BSGs is proposed. The efficiency uniformity of BSGs with an aperture of 430 mm× 430 mm is successfully controlled within a rms of 5% , which meets the specification of the large-aperture BSGs. For threshold characteristics of BSGs, the contamination and its cleaning of large-aperture BSGs are characterized with second ion mass spectroscopy quantitatively, and the cleaning flow of BSGs is developed and optimized. To remove the subsurface damage of fused silica, the fused silica substrate processing based on hydrofluoric acid and inductively coupled plasma etching is investigated. For improving the laser-induced damage threshold of the BSGs, it suggests that the HF acid etching method for large-aperture fused silica BSGs and the preparation method for BSGs integrated with sub-wavelength antireflection gratings should be developed in the future.