Optical elements containing semitransparent wavelike films.

Novel optical elements containing semitransparent wavelike films embedded into the bulk of transparent material, which form a reflection image without transmitted light distortion, are studied. The dynamic theory of light diffraction by a locally periodic multilayer semitransparent wavelike film is developed. A simple analytical formula for near Bragg diffraction order intensity is obtained for the case when only one diffraction order lies within the hologram angular selectivity. The phase modulation of light transmitted through the optical element containing wavelike films is estimated for single-layer and multilayer wavelike films with an arbitrary shape of surface. The restrictions on the structure parameters for which transmitted light distortions would be negligible are obtained. A new type of high-quality color hologram is proposed and shown to be feasible by calculation of hologram diffraction efficiency and spectral selectivity for three colors. Other possible applications, such as monochrome and color head-up and head-mounted displays, and imaging on spectacle lenses, are discussed.