From Huygens -Fresnel principle,formulas are derived for determing the distribution of the field and intensity on axis when focused Gaussian beam is diffracted at a circular aperture.

• 根据惠更斯一菲涅耳原理，推导出会聚病折光束经圆形孔径衍射后光轴上的场分布及强度分布表达式。