High frequency diffraction by wedges

Methods for handling high frequency fields are briefly reviewed. They are illustrated by the diffraction of a ray optical field by a curved wedge. The necessary formulas are collected or referred to for a direct application to the problem. The corresponding canonical problem, diffraction of a plane wave by a straight wedge, is presented from a point of view that shows the filiation of some diffraction factors and suggests generalization to other problems such as the diffraction by higher order wedges.