Simultaneous diffraction of two finite waves at a nonuniform mixed dynamic transmission grating

Diffraction of two light waves at a planar, finite transmission mixed grating is considered, utilizing the two-dimensional coupled-wave theory. Diffraction characteristics of two important cases, incident beams with uniform or Gaussian profiles, are presented. The dependence of the diffraction properties (beam profiles and diffraction efficiency) on the normalized parameter grating strength γ and on the phase shift ϕ of the grating with respect to the interference pattern of the readout waves in the case of pure phase gratings and absorption gratings is shown. The results are compared with the complete solution of the one-dimensional theory.