利用电子束蒸发方法在双面抛光的ZnSe基底上镀制单层Ge薄膜.在80 K~300 K温度范围内，采用PerkinElmer Frontier傅里叶变换红外光谱仪低温测试系统每20 K测量Ge单层在2~15 μm波长范围的透射率.采用全光谱反演拟合方法得到Ge单层在不同温度下的折射率.结果显示，Ge单层折射率均随波长增大而减小，且变化趋势基本相同.利用Cauchy色散公式对折射率波长色散关系进行拟合，得到Ge薄膜材料折射率温度/波长色散表达式为:n(λ,T)=3.29669+0.00015T+5.96834×10-6T2+0.41698λ2+0.17384λ4.最后，验证了Ge单层膜折射率温度/波长色散公式的准确性.

Germanium (Ge) films with physical thickness of 1600nm was deposited on ZnSe substrates by an electron beam evaporation system. The transmittance of Ge film in the range of 2 to 15 μm was measured by a PerkinElmer FTIR cryogenic testing system from 80 K to 300 K with a step length of 20 K. Then, the relationship between the refractive index and wavelength in the 2~12 μm region at different temperatures was obtained by the full spectrum inversion method fitting. It can be seen that the relationship confirms to the Cauchy formula. The relationship between the refractive index of Ge film and the temperature / wavelength can be expressed as n(λ,T)=3.29669+0.00015T+5.96834×10-6T2+0.41698λ2+0.17384λ4, which was obtained by the fitting method based on the Cauchy formula. Finally, the accuracy of the formula was verified by comparing the theoretical value obtained by the formula with the measured result.