Effect of the glass substrate on the efficiency of the different orders that propagate in a transmission sinusoidal diffraction grating

Abstract

In this work we study the effect of the glass substrate on the efficiencies of the different orders that propagate inside a transmission sinusoidal diffraction grating. Holographic optical elements are usually recorded on a photosensitive medium deposited on to a glass substrate. Therefore, the study of the entire system, namely the holographic element plus the glass substrate, is necessary. In this work we study the entire system by using the rigorous coupled-wave theory. As will be demonstrated, the effect of the glass is to generate an oscillatory pattern of the efficiency of the different orders around the average. The effect of the glass substrate is therefore sufficiently significant, and care must be taken in order to choose the appropriate thickness of the glass if maximum diffraction efficiency is to be achieved.