二氧化硅(SiO2)是一种重要的光学薄膜材料，通常采用电子束蒸发辅以离子束轰击的方式沉积，但在某些情况下，不能借用氧离子束的轰击。着重研究了不同沉积温度下无离子源辅助制备的二氧化硅薄膜的光学特性。通过直接在线的光学监控方式，获得薄膜生长过程的透射率曲线，并得到薄膜在真空中的折射率。采用真空在线光谱扫描和大气中离线的光谱扫描，结合光度法拟合得到薄膜折射率。结果表明由于基片温度的变化，二氧化硅薄膜的折射率会随着薄膜的厚度而改变，随着沉积温度的升高而变大，折射率值在1.34~1.41之间。

Silicon dioxide (SiO2) is a kind of important material of optical thin film. Usually the SiO2 thin films are prepared by electron beam deposition method with ion beam assisted deposition. But in some cases, we can not use the oxygen ion beam assisted bombardment. The research of the SiO2 films which are prepared at different deposition temperatures without ion beam assisted deposition. Through direct online optical monitoring mode, the growth process monitoring curves and the transmittance curves are obtained, the film refractive index in vacuum is calculated. Using the spectral scanning in vacuum online and in atmosphere offline, fitting the film refractive index by spectrophotometric. The results show that due to the substrate temperature′s change, the refractive index of the SiO2 thin film changes with the film thickness, and the refractive index increases with the temperature. The value is between 1.34~1.41.