Bragg diffraction of finite beams by thick gratings

Abstract

The theory of Bragg diffraction of finite beams by thick planar gratings is developed, using coupled-wave theory. Simple analytical expressions for the profiles of the transmitted and diffracted beams in the near field are obtained. Detailed diffraction characteristics for the important case of Gaussian-profile beams are presented. It is shown that the diffraction characteristics depend only on two normalized parameters, the grating strength, and a geometry parameter. The diffraction efficiency and the profiles of the transmitted and diffracted beams are calculated as functions of these two controlling parameters.