利用离子束溅射沉积制备了光学薄膜。基于椭圆偏振测量技术,研究了折射率、膜层厚度和表面层厚度与测试光斑大小的关系。研究结果表明,随着样品表面测试光斑尺寸的增加,薄膜折射率变小,膜层厚度、表面层厚度增加。使用反射光谱法和轮廓仪分别验证了各光学常数的光斑效应。研究结果表明,光学薄膜的折射率与膜层厚度具有弱横向非均匀性,采用大尺寸测量光斑能弱化这种非均匀性。 Optical films were prepared by ion beam sputtering deposition. Based on ellipsometry, the relationship between refractive index, film thickness, surface layer thickness and test spot size was studied. The results show that with the increase of spot size on the surface of the sample, the refractive index of the film becomes smaller and the thickness of the film and the thickness of the surface layer increase. The speckle effect of each optical constant was verified using reflectance spectroscopy and profiler respectively. The results show that the refractive index of the optical film and the thickness of the film have weak lateral non-uniformity, and the large size of the measuring spot can weaken the non-uniformity.