Diffraction of hermite-gaussian beams by Ronchi and aperiodic rulings

Abstract

In this paper, the diffraction of beams by Ronchi rulings is considered. The theory of diffraction is based on the Rayleigh-Sommerfeld integral equation with Dirichlet conditions. The diffraction of Gaussian and Hermite-Gaussian beams is studied numerically. The transmitted power and the normally diffracted energy are analyzed as a function of the spot size. The diffraction patterns obtained at maximum and minimum transmitted power are also deal with. We show that the two methods to determine the Gaussian spot size with Ronchi rulings which were experimentally compared in a previous paper [Rev. Mex. Fís. 53 (2007) 133] cannot be extended to the case of Hermite-Gaussian beams. Finally, for aperiodic rulings we propose a method for obtaining the Gaussian spot size by means of the normally diffracted energy.