溶胶凝胶法制备抗激光损伤SiO2疏水减反射膜

 通过溶胶-凝胶法，在碱性条件下水解缩聚正硅酸乙酯获得含有SiO₂颗粒的溶胶；以甲基三乙氧基硅烷在酸性条件下水解缩聚获得双链聚合物溶液，作为疏水基团的引入剂。用两者的混合物在玻璃片上旋转镀膜。利用光子相干光谱法、透射电子显微镜、小角X射线散射等方法研究了溶胶微结构，利用紫外-可见光谱仪和接触角测定仪测量薄膜的透射率和疏水性。单面反射率最低降至0.01%，对水接触角最高为118°。利用Nd:YAG激光（1 064nm）测量了薄膜的激光损伤阈值，随混合溶胶中双链聚合物含量的增加损伤阈值减小，但均高于20J/cm²（1ns脉冲）。由于薄膜既保持了纳米氧化硅薄膜的多孔性，又在颗粒及孔表面以甲基修饰，水对薄膜的浸润能力大大降低，因此薄膜的时间稳定性大大增强，同时也保证了较高的损伤阈值和透射率。

Preparation of hydrophobic anti-reflective SiO2 films for high laser resistance by Sol-Gel Process

A sol containing SiO_2 particles was prepared by the base catalyzed hydrolysis and polycondensation of tetraethoxysilane (TEOS) through sol-gel process. A solution containing double-chain polymer of methyltriethoxysilane (MTES) was also prepared under acid condition, as the introducer of water repellence. After mixing these two kinds of sols, spinning coating was used to deposit films on glass. Several techniquesphoton correlation spectrum,TEM and small angle X-ray scattering, were used to characterize the microstructure. The transmission and wet-angle for water of films were measured by UV-Vis and contact angle analyzer. The reflection can be reduced to 0.01% and the wet-angle for water was 118°at most. A Nd:YAG laser was used to determine the laser damage threshold of film at 1 064nm. The threshold decreased with the increasing content of double-chain polymer solution in sol mixture. But all the thresholds were higher than 20J/cm~2. Due to reserving porosity of nano-silica film and modifying the surface of pores by methyls , the wetting of water vapour to film weakened largely. The endurance of film improved , and high transmission and threshold were maintained.