退火对ZrO2薄膜微结构及激光损伤阈值的影响

利用电子束蒸发方法在Yb:YAG晶体和熔融石英衬底上沉积单层ZrO2薄膜,分别在673 K和1 073 K的温度下经过12 h退火以后,通过X射线衍射(XRD)分析了薄膜晶相,计算了薄膜的晶粒尺寸;利用表面热透镜技术获得了薄膜的吸收;测量了退火后薄膜的激光损伤阈值.实验结果表明:两种衬底上的薄膜结构受到退火温度和衬底表面结构的影响,高温退火有利于单斜相的形成,含单斜相的ZrO2薄膜具有较高的激光损伤阈值,而由于衬底的吸收,Yb:YAG晶体上薄膜的损伤阈值远小于石英衬底上薄膜的损伤阈值.

ZrO₂ coatings were deposited on different substrates of Yb∶YAG and fused silica by electron beam evaporation. After annealed for 12 hours at 673 K and 1 073 K respectively, weak absorption of coatings was measured by surface thermal lensing, and then laser-induced damage threshold was determined. The crystalline phase of ZrO₂ coatings and the size of the crystal grain were investigated by X-ray diffraction. It is found that microstructure of ZrO₂ coatings is dependent on both annealing temperature and substrate structure, anneal at high temperature helps to produce monoclinic phases, and coatings containing monoclinic phases have higher damage threshold than others. Due to the strong absorption of Yb∶YAG, damage threshold of coatings on Yb∶YAG is much less than that on fused silica.