In this paper we show that the possibility of obtaining the high values of efficiency of relief-phase holographic gratings
formed in the photo-thermoplastic recording process holds not only due to the non-sinusoidal profile form, but also due to
the effect of optical coating that appears in the two-layer system of photo-semiconductor – deformed thermoplastic.
Analyzed are the conditions, under which takes place the antireflection optical coating, reducing unwanted reflections from
surfaces and thereby enhancing efficiency. It is shown that by careful choice of the thicknesses and refractive indices of the
layers materials the efficiency of holographic gratings can be improved by 2-5 %.
