Application of the Dynamical Theory of X-Ray Diffraction to Holography

Abstract

The concepts of the dynamical theory of x-ray diffraction are applied to optical holography. A plane-grating hologram is the assumed diffraction element and its behavior is shown to be consistent with that of its x-ray counterpart, namely a thin, one-dimensionally periodic structure. Evidence is cited which corroborates the theory. In particular, an anomalous transmission of light through the plane-grating structure, at the Bragg angle, is reported-referred to as the Borrmann effect in the x-ray-crystal situation-which in x-ray optics is taken as prima facie evidence for the dynamical theory. The usually observed subsidiary maxima about the Bragg peak and their reported asymmetry are explainable in terms of the dynamical theory as effects due to a finite lattice. The minimum angle of deviation found in holograms, so familiar to prisms and line gratings, is described as a finite-lattice effect. It is concluded that the dynamical approach in holography is a useful one for the thick emulsion, whereas the simple kinematic theory is more adequate for thin emulsions. However, attention is drawn to the use of the dynamical theory even for the case of thin emulsions to help provide some physical insight into the diffraction of light by holograms.