Ge基底LaF<sub>3</sub>-ZnS-Ge高耐用中波红外增透膜

Ge基底LaF₃-ZnS-Ge高耐用中波红外增透膜

摘要: 研究了LaF3材料的蒸发特性及其在2.5~12 m红外波段的光学常数，并将LaF3晶体作为低折射率材料在Ge基底上制备了中波红外3.7~4.8 m波段高耐用性增透膜。SEM照片显示，基于LaF3材料的高耐用性增透膜表面纳米晶粒分布均匀致密，表面光洁度高。利用傅里叶变换红外光谱仪测试了其光谱特性，在3.7~4.8 m波段，峰值透射率达到99.4%，双面镀膜平均透射率由47.7%提高到98.8%。牢固度、耐久性等环境试验结果显示，膜层在保持高的光学性能的同时还可以在较为严苛的恶劣环境中使用

Abstract: Evaporation characteristics and optical constants of LaF3 materials in 2.5-12 m infrared band were investigated. With low refractive index LaF3 materials, high-durability antireflection (AR) coatings in 3.7-4.8 m medium-wavelength infrared bands were designed and fabricated on Ge substrate. SEM image of the AR coatings with the LaF3 shows that the surface nanocrystals is uniform and densified. The measured optical properties by Fourier tranform infrared spectrometer indicate that the peak transmittance is as high as 99.4%, and the average transmittance increases to 98.8% from 47.7% in 3.7-4.8 m after double-sided coating. The firmness and durability environmental tests signify that this AR coating can work in harsh environment while maintaining good optical properties.