为了验证空气隙的厚度是否对偏光棱镜的透射比产生影响，对格兰－泰勒棱镜和格兰－付科棱镜的透射比进行了详细的理论分析，并利用UV－3101分光光度计分别对两只格兰－泰勒棱镜和两只格兰－付科棱镜的透射比进行了实验测试，发现格兰－泰勒棱镜的透射比(85%左右)明显高于格兰－付科棱镜(50%左右)。理论分析表明，对于严格的准直光束，两种棱镜的透射比均随波长的变化而振荡，且这种振荡对格兰－付科棱镜强于格兰－泰勒棱镜；但在分光光度计上的测试并未出现振荡，这说明对于非严格准直的光束，空气隙的厚度并不影响棱镜的透射比。

In order to verify whether the thickness of air-gap would influence the prism's transmittance,the transmittance of Glan-Taylor prism and Glan-Faucault prism is theoretically studied. The transmittance of two-Glan-Taylor prisms and two-GlanFaucault prisms is tested with a UV-3101 spectral photometer,and the results are found the transmittance of Glan-Taylor prism(about 85%)is obviously higher than that of Glan-Faucault prism(about 50%). For strictly collimating light,the transmittance of these two types of prism varies with the wavelength change,and this vibration is stronger for Glan-Faucault prism than for GlanTaylor prism. However,the experimental result tested by spectral photometer doesn't have vibration,which shows that for nonstrictly collimating light,the thickness of air-gap doesn't influence the prism's transmittance.