Influence of interference factors on extinction ratio measurement of polarizing prism

In order to eliminate Glan-Taylor prism transmission spectra curve fluctuation and improve the measurement accuracy of extinction ratio, the quadratic curve fitting method was adopted to confirm the extreme point position of transmission curve by using polarizing prism as analyzer. The secondary light intensity was measured. And the incident end and transmission end of prism, reflection end and exit end of the cementing layer were analyzed theoretically. Then, variation law of the transmission spectrum of prism at different angles was used to explain the degree of interference. The measurement results show that this method eliminates the wave interference effect and improves the accuracy of the extinction ratio. The results solve the measurement accuracy problem of extinction ratio of air-spaced polarization prisms, and it provides the reference to use polarizing prism correctly.