疏水性SiO_2基减反膜稳定性研究

Study on Stability of SiO_2-Based Moisture-Resistant Antireflective Coatings

在SiO2溶胶合成阶段进行化学改性,将六甲基二硅氮烷(HMDS)引入SiO2溶胶,制得稳定的胶体,胶体中SiO2纳米颗粒表面的亲水性Si-OH基团被疏水性的Si-O-Si(CH3)3基团取代。采用旋转法在磷酸二氢钾(KDP)晶体表面涂膜,涂膜晶体峰值透射率99%以上。膜层光学均匀性良好,表面粗糙度均方根值为0.94 nm。膜层疏水性能好,水接触角达到140°。涂制疏水性SiO2基减反膜的KDP晶体无需热处理就具有较好的疏水防潮性能,与目前激光器使用的防潮减反双层膜相比,在室温高湿度条件下涂膜晶体透射率下降情况大致相当。旋转涂膜可以有效解决三倍频晶体入光面与出光面共3个波段需减反的问题。

The Si-OH group on particle in the silica colloidal suspension is modified to Si-O-Si（CH3）3 non-polar hydrophobic group using hexa-methyl-disilazane（HMDS）.The organic modified silica antireflective（AR） coatings that coated on potassium di-hydrogen phosphate（KDP） crystal and silica glass substrates by spinning method,has good moisture-resistant property.The transmission of coated substrate is above 99%.The optical roughness root-mean-square value is 0.94 nm and the water contact angle of coating is about 140°.The HMDS modifies SiO2 sol in non-polar solvents which need no treatment can be used in KDP crystals.In the condition of the room temperature and high humidity,the transmittance decrease of KDP crystals with the moisture-resistant（MR） AR coating is equal to the MR/AR two-layer coating.The reflection losses at three wavelengths from two surface of the tripling crystal can be minimized by spin coating.