薄膜材料的生长过程随镀膜机尺寸的增大而呈现新的规律，为制备膜层均匀性好、材料均质的大尺寸光学元件，分别在不同离子源能量、沉积压强、基板加热温度及基板转速条件下，采用离子辅助电子束蒸发方法制备了不同单层SiO2薄膜样品; 利用分光光度计及椭偏仪分别对样品的透过率及椭偏参数进行测量，并对测量结果进行拟合得到不同样品的折射率及非均质特性。实验结果表明，工件架转速是使大尺寸SiO2薄膜材料产生非均质特性的主要影响因素，离子源能量、基板温度、沉积压强通过影响材料生长过程对材料的非均质特性产生调控; 对于大尺寸薄膜光学元件，工件架转速存在限制的条件下，优化其他工艺参数可以获得均质SiO2薄膜材料，该结果对于制备具有优良性能的大尺寸薄膜光学元件具有借鉴意义。

With increasing of deposition machine’s dimension, the growth process of thin film material will show new phenomena. In order to get homogenous large caliber optical thin film, different single SiO2 layers were fabricated using ion-assisted electric gun evaporation under different ion source energy, deposition pressure, substrate temperature and different rotation speed. Spectroscopic ellipsometry and spectrometer were used to measure SiO2 samples’ ellipsometric parameters and transmission spectra, respectively. Refractive index and it’s distribution were got by fitting the corresponding measurement results. It is shown that rotation speed is the main cause for the inhomogeneity of large caliber SiO2 thin film. Ion source energy, deposition pressure and substrate temperature can modulate the inhomogeneity by affecting SiO2 thin film’s growing process. When the rotation speed is limited for large dimension optical elements, homogenous optical thin film can also be got by optimizing other deposition parameters.