基于溶剂热反应快速沉积ZrO_2-基激光光学薄膜

摘要

Zirconia-based optical thin films have been facilely deposited via a modified sol-gel route,which involved the alcothermal treatment of a mixture of zirconium n-propoxide-acetic acid-ethanol at 423 K and a spin-coating process.The compositional dependence of the microstructure of colloidal systems,the structural and optical properties,as well as the laser-induced damage resistance of films,was characterized.It was demonstrated that,in the present system,the reactions such as esterification,chelation,and hydrolysis-condensation must coexist.And the preference of any of these reactions depends on the system composition（especially the molar ratio of acetic acid to zirconium n-propoxide）,and ultimately determines the structure of the colloidal systems.With the proper selection of the processing parameters,the stable uniform sols comprising particles with mean hydrodynamic diameter of 10 nm~15 nm can be obtained,which enables the rapid deposition of high-performance zirconia-based optical films with excellent surface planarity,comparatively high refractive index of 1.633（at 632 nm）and high laser-induced damage threshold of 34.7 J/cm2（at 1 064 nm,3 ns pulse duration,and R/1 testing mode）.%基于丙醇锆-乙酸-乙醇混合体系的溶剂热反应（423 K,10 h）合成了稳定的ZrO2-基溶胶,采用旋转镀膜技术在K9玻璃基片上制备了ZrO2-基光学薄膜。借助动态光散射、傅里叶变换红外光谱、原子力显微镜、紫外/可见/近红外透射光谱、FilmTMTek 3000型薄膜分析仪以及强激光辐照实验对溶胶与薄膜的微观结构及光学性能进行表征。研究发现,通过与溶剂乙醇的酯化反应和与丙醇锆的配合反应,乙酸具有温和地提供反应水和降低丙醇锆水解活性的双重作用。在各工艺参数适当配置的情况下,采用该方法可以快速合成颗粒流体力学直径为10 nm~15 nm的溶胶,由此沉积的薄膜具有平整的表面、较高的折射率1.633（测试波长为632 nm）和高的激光损伤阈值34.7 J/cm2（激光波长为1 064 nm,脉冲宽度为3 ns,＂R/1＂测试模式）。