Volume transmission and reflection holograms in the high-concentrated composite of phenanthrenequinone in polymethylmethacrylate

A comparative experimental study of the recording of volume phase transmission and reflection holograms in the layers of polymethylmethacrylate containing 2-3 mol.% of phenanthrenequinone has been performed. The angular and spectral selectivities of the holograms depending on the recording conditions have been analyzed. It has been demonstrated that due to high concentration of photosensitive molecules and the ability of post-exposure thermal amplification of the holograms, a diffraction efficiency up to 80% even with a small thickness of polymeric layers (~100 µm) can be achieved. After thermal amplification the holograms were fixed by irradiation in the spectral range of 450-500 nm in order to acquire their stability against heating, visible and IR radiations. Thereby, it was demonstrated that by applying relatively thin photopolymeric layers with high concentrations of phenanthrenequinone high diffraction efficiency at a fairly low angular selectivity can be achieved, thus offering a significant optical efficiency of polymeric holographic elements.