The Fresnel Picture of Scattering of a Plane Wave on a Diffraction Grating.

Below, we consider the problem of scattering of a plane wave by a diffraction grating in a Fresnel pattern, usually studied in the Fraunhofer approximation. For an approximate description of the scattered field, it is necessary to introduce two-wave parameters: the wave parameter over the observation area and the wave parameter for the region where the sources are located. The intensity maxima of the diffracted field in the Fresnel pattern are obtained for the angles corresponding to the intensity maxima in the Fraunhofer pattern. It is shown that the field intensity on the side lobes of the diffraction pattern takes on the maximum possible value. [ABSTRACT FROM AUTHOR]