在惯性约束聚变(ICF)装置中大量使用具有变频特性的水溶性磷酸二氢钾(KDP)类晶体材料。在KDP晶体上镀制薄膜材料成为保护KDP晶体的有效措施。以正硅酸乙酯(TEOS)为原料，采用溶胶-凝胶法和提拉方式制备膜厚λ/4的增透膜，再采用具有高憎水特性、高透射率、低折射率的氟聚合物AF2400在FC-75的可溶解特性，在SiO2增透膜上旋涂AF2400防潮膜。对薄膜的表面形貌、疏水性能、光学性能和抗激光损伤阈值等进行了测试。结果显示，AF2400-SiO2复合光学薄膜表面平整，折射率为1.21，疏水角可以达到110°～120°，抗激光损伤阈值为19.5 J/cm2，是性能优良的疏水光学薄膜，可用于三倍频晶体KDP的保护。

Inertial confinement fusion (ICF) establishment needs lots of high quality, large caliber and non-linear optical material potassium dihydrogen phosphate (KDP), which is water-soluble crystal. It is necessary to prepare a moisture-barrier protective film with good performance on the surface of KDP crystals. Antireflective SiO2 coating has been prepared by tetraethyl orthosilicate (TEOS) and sol-gel route with dip coating method. The surface of SiO2 film was disposed with teflon AF2400. The properties of the AF2400-SiO2 composite film had been characterized and measured by atomic force microscope (AFM), Fourier transform infrared (FTIR), UV-VIS-NIR spectroscopes etc. The experimental results show that the light transmission of AF2400-SiO2 composite film is 97.7% at 355 nm, the refractive index is 1.21. The AF2400-SiO2 composite films have fine water-repellent performance, high laser damage threshold (19.5 J/cm2) and excellent optical property. The composite film can be used for protection of KDP crystal.