Optical scattering analysis of the diffraction distortion of a two-dimensional reflection grating

Theoretical and experimental studies of the diffraction of a two-dimensional reflection grating are performed in this paper. Based on the theory of optical scattering, the light field in the Fraunhofer diffraction region is deduced, and the general expression of the diffraction field is given in the form of the wave vectors of the diffracted wave and the incident wave. Then the coordinate of the diffraction order is obtained. The calculation results show that the diffraction distortion of the grating appears when the grating is illuminated by the oblique incident light wave and the distortion is restricted on the diffraction of the grids varying along the direction perpendicular to the plane of incidence. The orbit equation satisfied by the distortion diffraction orders is presented. The experimental results verify adequately this diffraction distortion rule of the grating, and they agree very well with the theoretical results. (C) 2009 Optical Society of America