Analysis and Comparison of Fraunhofer Diffractive Condition Between Diffractive Integral and Fresnel's Wave Zone Method

Fraunhofer diffractive condition without a lens is compared based on diffractive integral and Fresnel's wave zone method,which proves that Fraunhofer diffractive condition obtained from the two methods is consistent.The method of Fresnel's wave zone could help students to understand Fraunhofer diffraction better.