溶胶-凝胶SiO_(2)减反膜的制备与光学性能研究

Preparation and Optical Properties of Sol-Gel SiO_(2)Antireflective Films

碱催化溶胶-凝胶多孔SiO_(2)减反膜具有优异的光学性能及抗激光损伤性能,是高功率激光装置中的重要组成部分,但其与光学元件之间的结合强度低,使得膜层易发生接触破坏。本研究以“神光II”高功率激光装置溶胶-凝胶多孔SiO_(2)减反膜为基础,通过提拉法在其表层涂覆致密的SiO_(2)薄层后得到机械强度提升的双层SiO_(2)减反膜(SiO_(2)-MTES),并与常用的单层氨固化SiO_(2)减反膜(SiO_(2)-HMDS)进行相关应用性能的综合比较。结果表明,涂覆SiO_(2)-MTES的熔石英在约800 nm处的峰值透过率大于99.6%,运用1-on-1激光损伤阈值测试方法测得该双层SiO_(2)减反膜的零几率激光损伤阈值为51.9 J/cm^(2)(1064 nm,9.1 ns),与涂覆SiO_(2)-HMDS的性能相当。同时,SiO_(2)-MTES膜层与水的接触角达到117.3°,且在相对湿度大于90%的高湿环境中膜层的透过率较稳定。多次擦拭实验结果表明SiO_(2)-MTES的耐摩擦机械强度明显优于SiO_(2)-HMDS,有效提升了膜层与光学元件之间的结合强度。

Base-catalyzed sol-gel porous SiO_(2)antireflective film,an important part of high power laser(such as"Shenguang II"high power laser)facilities,has excellent optical properties and laser damage resistance.However,its low binding strength with optical components can lead to the film frustrated with contact destruction.Based on this antireflective film,a double-layer SiO_(2)antireflective film(SiO_(2)-MTES)was prepared with improved mechanical strength by coating a thin dense SiO_(2)film on its surface using dip coating method.Then the SiO_(2)-MTES was compared with a commonly used single-layer ammonia cured SiO_(2)antireflective film(SiO_(2)-HMDS).Results indicate that the peak transmittance of the fused quartz substrate coated with SiO_(2)-MTES reaches greater than 99.6%at about 800 nm and the zero probability laser damage threshold is measured to be 51.9 J/cm^(2)(1064 nm,9.1 ns)by 1-on-1 laser induced damage threshold testing method,equivalent to the performances of the fused quartz substrate with SiO_(2)-HMDS.Meanwhile,the contact angle between SiO_(2)-MTES and water reaches 117.3°,and the transmittance stability of the SiO_(2)-MTES is good in the high humidity environment with relative humidity greater than 90%.Results of multi-wiping experiments show that the friction-resistant mechanical strength of SiO_(2)-MTES is significantly better than that of SiO_(2)-HMDS,which effectively improves the binding strength between the film and the optical components.