FRAUNHOFER-DIFFRACTION OF A SLIT APERTURE BETWEEN A KNIFE-EDGE AND A METAL CYLINDER

The Fraunhofer diffraction pattern of a slit aperture formed between a reference knife-edge and a metal-cylinder surface is different from t hat of an ideal slit aperture. This pattern should include reflected l ight coming from both the front and rear sides of a cylinder surface. To investigate the influence of light reflected from the cylinder surf ace, we discuss the theoretical consideration based on the simple mode l of the reflected light on the surface. The experimental setup is des igned and constructed to measure the actual diffraction pattern produc ed by the slit between the knife-edge and the cylinder surface. As a r esult it is obvious that the reflection of diffracted light on the rea r side is dominant in both the simulation and the experiment.