Analysis of optical propagation in thick holographic gratings

A method of analyzing optical propagation in thick holographic gratings by decomposition of the thick material into thin gratings is discussed. The method is readily applicable to study propagation in multiple gratings of arbitrary spatial frequency and orientation recorded in the same thick emulsion. Applied to the double grating case, the method predicts strong cross-coupling between the two gratings for proper relative slope of the gratings. Results are given.