衍射花样及其近似描述

Diffraction Pattern and Its Approximate Description

导出了描述夫琅和费衍射的正确公式，讨论了菲涅耳衍射和夫琅和费衍射的物理意义、两者间的逻辑关系，以及倾斜因子ｋ（θ）对衍射花样的影响。指出一些傅里叶光学文献中的“菲涅耳衍射公式”和“夫琅和费衍射公式”均只能在观察距离ｚ不太小也不太大的近轴范围内近似成立，ｚ越大成立的角范围越小，当ｚ趋向于∞时，成立的角范围趋向于零。

A correct formula describing Fraunhofer diffraction is obt ained.The physical significance and the logical relation of the Fresnel diffract ion and the Fraunhofer diffraction,along with the influence of inclination facto r on diffraction pattern are discussed in detail.It is pointed out that the “Fr esnel diffraction formula” and the “Fraunhofer diffraction formula” are only approximately satisfied for paraxial region at an observing distance z which is neither too small nor too large.The larger z is,the smaller the angle scope θ 0max of application is .When z→∞,θ0max→0.