作　　者： ;

机构地区： 华南理工大学理学院物理系

出　　处： 《大学物理》 2011年第2期58-61,共4页

摘　　要： 光经圆盘、细丝等实屏衍射后,衍射光场中其几何阴影中心有不为零的光强分布.显然这是阐述光的波动性的最好例证,它比圆孔、单缝之类的光孔衍射更具说服力.然而对圆盘等的衍射中心亮点(如泊松点)的论证通常都是从菲涅耳衍射出发,但是在绝大多数非物理类专业的大学物理中,对光的衍射的具体分析都只涉及夫琅禾费衍射,因而给学生对于上述问题的理解造成了障碍.本文以理工科学生熟悉的夫琅禾费衍射为讨论对象,分别用菲涅耳积分公式和巴比涅原理对上述问题作简单的半定性半定量分析论证.两种方法给出相同的论证结果.且不难看到,这是浅显易懂的论证方式. The intensity of diffracted light at the geometric centre of the diffraction optical field is always not ze- ro through diffraction by a real obstacle screen such as a disk or a filament. Clearly, this is the best demonstration of the wave nature of light, and so it is more convincing than that of diffraction by an aperture such as a circular ap- erture or a slit. However. the theoretical analysis for the light spot （such as Poisson point） at the obstacle diffrac- tion field center is usually based on the Fresnel diffraction, while for the majority students who are not majored in physics, they are just required to have the knowledge of Fraunhofer diffraction in the course of university physics, thus it causes difficulty to them to understand the related questions. In this paper, the starting point of argument is directly based on the Fraunhofer diffraction which is familiar to the students majored in science and engineering. By use of the Fresnel integral formula or Babinet principle combined with simple analyze method of semi-qualitative and semi-quantitative, we give two easily ways for solving the problem. It is seen that the argument method is helpful for students to understand the relevant questions.

关 键 词： 光的衍射 惠更斯 菲涅耳原理 巴比涅原理 大学物理

领　　域： [机械工程] [理学] [理学]