Correlation between Rayleigh-Somerfield diffraction and physical optics integration

To calculate the propagation of electromagnetic field in quasi-optics, the internal consistency and distinction between different approaches were researched respectively from Rayleigh-Somerfield scalar diffraction integration and vectorial physical optics integration. The two integration methods were firstly distinguished from physical conception, and then the consistency was discussed in the condition that electromagnetic field propagates between parallel planes. Propagation of the Gaussian beam was numerically simulated respectively by the two integration methods and compared with the analytical solution result. Precision of the two methods in handling problems of electromagnetic field propagation and different applications in vectorial diffraction problems was finally proposed.