A polarizing beam splitter is a cube structure formed by coating multiple layers of dielectric interference films on the inclined surface of one of the right angle prisms. The polarizing film on the inclined surface can split the incident unpolarized light into two perpendicular polarized light beams, with P-polarized light completely passing through and S-polarized light completely reflecting at a 45 ° angle, and S-light and P-light forming a 90 ° angle. The usual indicators for testing the separation of P and S light are the transmittance extinction ratio, and the TP: TS ratio can be greater than 1000, 3000, 5000 according to requirements. Secondly, the polarizing beam splitter prism has the characteristics of low stress, high extinction ratio, good imaging quality, and small beam deflection angle. The wavelength covers the range of 400-1600nm and can be used for polarization, polarization detection, light intensity modulation, and other occasions.