Examination of beam propagation in misaligned holographic gratings and comparison with the acousto-optic transfer function model for profiled beams

A transfer function formalism developed earlier for the propagation of profiled optical beams through acousto-optic Bragg cells is revisited and applied to a thick holographic grating. The results based on the holographic coupled wave model and the acousto-optic multiple scattering model are shown to be compatible, and equivalent parameters such as the Q and grating strength are defined for the two systems. Results for a Gaussian spatial profile are numerically computed and compared. For the holographic grating, a profiled beam may be interpreted as an angular misalignment or Bragg-angle mismatch problem. The case of Bragg-wavelength mismatch is also investigated for the case of a polychromatic READ beam with a uniform and a Gaussian amplitude spectrum. The resulting spatial amplitude distribution of the scattered order at the grating output is plotted as a function of the departure from the correct Bragg direction. (C) 1999 Society of Photo-Optical Instrumentation Engineers. [S0091-3286(99)00807-7].