LBO晶体上1 064，532 nm倍频增透膜的镀制及性能分析

 用电子束蒸发沉积方法在X切LBO（X-LBO）晶体上镀制了两种不同膜系结构的1 064和532 nm倍频增透膜，其中一种膜系结构为基底/ZrO₂/Y₂O₃/Al₂O₃/SiO₂/空气，另一种为基底/0.5Al₂O₃/ZrO₂/Y₂O₃/Al₂O₃/SiO₂/空气，两种膜系结构的主要差别在于有无氧化铝过渡层。测量了薄膜的反射率光谱曲线，发现两种增透膜在1 064和532 nm处的反射率均小于0.5％，实际镀制结果与理论设计曲线的差异主要是由材料折射率的变化引起的。且对样品在空气环境中进行了温度为473 K的退火处理，结果发现两种膜系结构均表现了较优异的光学性能，氧化铝过渡层的加入使薄膜具有强的热应力性能。

Fabrication and performance evaluation of 1 064, 532 nm frequency-doubled antireflection coating for LBO crystal

Two different types of 1 064,532 nm frequency-doubled antireflection coatings for X-LBO were deposited by electron beam evaporation.One stack is substrate/ZrO2/Y2O3/Al2O3/SiO2/air,and the other is substrate/Al2O3/ZrO2/Y2O3/Al2O3/SiO2/air.The main difference between the two was the presence of alumina interlayer,and the optical behavior and adhesion between film and LBO substrate were investigated.Both coatings showed good optical performance that the reflectance of the coatings at 1 064 nm or 532 nm is less than 0.5%,but the coating with alumina interlayer showed stronger adhesion after annealing at 473 K for 2 h by contrast with that without alumina interlayer,which indicated that the alumina interlayer helped the coating resist the strong thermal stress from the thermal expansion mismatch between film and LBO substrate and improved the adhesion.