采用磁控溅射法制备了不同厚度的锑基铋掺杂薄膜，用X射线衍射(XRD)和透射电子显微镜(TEM)研究了薄膜结构随厚度的变化。利用椭圆偏振法测定了样品薄膜在近红外波段的光学常数与光学带隙，研究了膜厚对样品薄膜光学常数和光学带隙的影响。结果表明，膜厚从7 nm增加至100 nm时，其结构由非晶态转变为晶态。在950～2200 nm波段，不同厚度薄膜样品的折射率在4.6～8.9范围，消光系数在0.6～5.8范围，光学带隙在0.32～0.16 eV范围。随着膜厚的增加，薄膜的折射率和光学带隙减小，而消光系数升高；光学常数在膜厚50 nm时存在临界值，其原因是临界值前后薄膜微观结构变化不同。

Antimony-based bismuth-doped films with different thicknesses are deposited by magnetron sputtering method. The structure of samples with different thickness is studied by X-ray diffraction (XRD) and transmission electron microscope (TEM). The optical constants and optical band gap of the samples in range of 950～2200 nm are measured by spectroscopic ellipsometry. The influence of thickness on optical constants and optical band gap is investigated. The results show that the structure of the samples transforms from amorphous state into crystalline state when the thickness increases from 7 nm to 100 nm. In wavelength range of 950～2200 nm, the refractive index, extinction coefficient and optical band gap of the samples with different thickness are in range of 4.6～8.9, 0.6～5.8 and 0.32～0.16 eV, respectively. The refractive index and optical band gap decrease and the extinction coefficient increases with the increase of thickness. At thickness of 50 nm, the optical constants have a critical value, which results from the change of microstructure when thickness is larger or smaller than the critical value.