以离子束溅射沉积(IBSD)方法制备了Al2O3、Nb2O5单层膜，用红外可变角度光谱椭圆偏振仪(IR-VASE)测试了薄膜的光学常数。用原子力显微镜(AFM)测量了单层膜的表面形貌及表面粗糙度，计算了单个表面的总积分散射(TIS)。以Nb2O5 和Al2O3 为高低折射率材料设计并制备了2.7 μm 高反射膜。最后对单层膜进行了环境实验检测。结果表明，制备的薄膜在中红外波段具有高的折射率和低的消光系数，光滑的表面特性和极低的表面散射损耗；在2.7 μm 波段没有发现由于水吸收导致的消光系数的增大；制备的反射膜在2.7 μm 反射率达到了99.63%，接近于理论计算值。薄膜顺利通过了一系列环境实验，显示其优良的环境稳定性。

Single layer Al2O3，Nb2O5 films are prepared by ion beam sputtering deposition (IBSD). Optical constants are measured by infrared variable angle spectroscopic ellipsometer (IR- VASE). Surface topography and roughness of these films are investigated by atomic force microscopy (AFM). 2.7 μm dielectric mirror is prepared using Nb2O5 and Al2O3 as high and low refractive index materials. The environmental stability of single layer films is tested. The results show that asdeposited films have relatively high refractive index, low extinction coefficient, excellent surface morphology and extremely low scattering loss. There is no water absorption in these films which can lead to great increase in extinction coefficient at the 2.7 μm band. The measured reflectance of 2.7 μm Nb2O5/Al2O3 mirror is 99.63% , close to theoretical value. All the films have passed the environmental tests，showing that oxide coatings fabricated by IBSD are stable and durable in hash environment.