Effect of high-temperature ablation on protective coating of ZnS optical windows

While infrared （IR） hard protective film of ZnS optical window is used in high temperature environment, its optical and mechanical stabilities are the premise of the IR optical system. IR hard protective film is deposited on ZnS optical windows by chemical vapor deposition （CVD）, and ablation experiments are done to the maximum temperature the film can endure. The effects of ablation temperature on the optical and mechanical properties of the protective films are investigated by surface profiler, Fourier-transform infrared （FTIR） spectrometry, IR ellipsometer, and Metallographic microscope. It is shown that the optical and mechanical properties of ZnS hard protective film change little before 500 ℃, and film refractive index and optical thickness reduce while ablation temperature surpassing 500 ℃, forming crater-like ablation structure, which leads to the reduction of film combination significantly.     

SiO2薄膜内部短程有序微结构研究

SiO₂薄膜是重要的低折射率材料之一, 针对离子束溅射(IBS)和电子束蒸发(EB)的SiO₂薄膜, 采用红外光谱反演技术获得在400–1500 cm^-1波数内的介电常数, 通过对介电能损函数的分析获得了两种薄膜在横向和纵向光学 振动模式下的振动频率和Si–O–Si键角.研究结果表明, 在EB SiO₂薄膜短程有序范围内, SiO₄的连接方式主要是类柯石英结构、3-平面折叠环和热液石英结构的SiO₄连接方式; 在IBS SiO₂薄膜短程有序范围内, SiO₄的连接方式复杂主要是类柯石英结构、3-平面折叠环、 4-平面折叠环结构和类热液石英结构. 关键词： 2薄膜')" href="#">SiO₂薄膜 离子束溅射 电子束蒸发 短程有序     

Microstructure and optical properties of Ge films prepared by ion beam assisted deposition

Germanium （Ge） films are prepared on BK7 glass and multispectral zinc sulfide （m-ZnS） substrates by ion beam assisted deposition （IBAD）. The effects of substrate temperature, deposition rate, and ion energy on the microstructure and optical properties of the films are investigated. It can be concluded that Ge film deposited with higher rate or ion energy has more optical absorption, while ion energy below 150 eV helps to reduce film absorption. Film refractive index increases with film deposition rate and bombardment ion energy while it is below 300 eV. And higher growth rate or bombardment ion energy can weaken film diffraction intensity.     

金属氧化物薄膜在中波红外光谱区内光学常数色散特性

基于金属氧化物薄膜材料在中波红外波段应用的需求,研究了含水状态的TiO2、HfO2、Ta2O5和Y2O34种金属氧化物薄膜在中波红外波段内(2.5~5μm)光学常数的色散特性。利用电子束蒸发沉积技术,在超光滑的硅表面制备了4种氧化物薄膜,基于洛仑兹振子介电常数色散模型,通过透射率光谱反演计算了4种氧化物薄膜的光学常数。研究结果表明:4种氧化物均有少量的水分子、羟基,水含量从少到多的薄膜依次为TiO2、HfO2、Ta2O5和Y2O3,在远离水吸收的位置,消光系数从小到大的薄膜分别为TiO2、HfO2、Ta2O5和Y2O3;在电子束蒸发沉积工艺条件下,为了降低水的影响,TiO2和HfO2是中红外波段较为理想的金属氧化物薄膜材料。