Geometrical theory of diffraction-a historical perspective

Abstract

The geometrical theory of diffraction is a very convenient and easy method of calculating diffraction patterns, and an elegant approach to the problems of Fresnel diffraction at apertures and obstacles. In spite of its long and chequered history, it has not found sufficient emphasis in the standard literature on optical diffraction. Between Young and Keller (1962), the Indian school (1917-45) led by Raman was active in the field.