为了进一步提高TiO2薄膜的光学特性和激光损伤阈值, 采用电子束蒸发技术在K9玻璃上沉积了单层TiO2薄膜, 并用Ar/O混合等离子体对样品进行后处理。通过研究薄膜光谱特性、表面缺陷密度、薄膜表面形貌、薄膜损伤阈值以及薄膜损伤形貌, 分析了等离子体后处理时间对TiO2薄膜激光损伤特性的影响。实验结果表明, 随着等离子体后处理时间的增加, 薄膜折射率及致密度提高, 物理厚度减少, 表面粗糙度下降, 表面缺陷密度先减少后增加; 在1 064 nm激光辐射下, TiO2薄膜的激光损伤阈值从未经等离子后处理的5.6 J/cm2提升至后处理20 min的9.65 J/cm2, 提升幅度高达72.3%, 因此能够更广泛更稳定地应用在激光器中。

To improve the optical properties and laser damage threshold of TiO2 films and to ensure their wider use and greater stability in lasers, TiO2 films were deposited on K9 glass using electron beam evaporation technology, and the samples were post-treated with Ar/O mixed plasma. The effects of plasma post-treatment time on the laser damage characteristics of TiO2 thin films were analyzed by measuring the film spectral characteristics, surface defect density, surface topography, damage threshold, and damage topography. The experimental results showed that the refractive index and fill density of the films increased with increasing post-treatment time, whereas the physical thickness and surface roughness decreased. In addition, the surface defect density first decreased and then increased. After a 20-min post-treatment, the LIDT of the TiO2 film samples increased from 5.6 to 9.65 J/cm2 under a 1 064-nm laser irradiation, representing an increase of 72.3%.