Self-Processing,Diffusion-Based Photopolymers for Holographic Applications

The new photopolymers for holographic applications described herein are based on a cross-linked matrix in which the holographic grating is formed by photo-polymerization of guest monomers in an interference pattern of the recording light. Diffusion of monomer, triggered by this photo-polymerization, from the dark to the bright fringes of the interference pattern is the key parameter for creating high modulation in refractive index Δn during hologram recording. This leads to bright visual volume holograms with high diffraction efficiency. The holographic photopolymers are self-processing. After recording the hologram only (incoherent) light exposure is necessary to bleach the final product and fix the hologram. Unlike earlier photopolymers used in holography, these new materials offer the advantages of no chemical or thermal processing combined with low shrinkage and detuning. Additionally, due to good light sensitivity the formation of the holograms is fast and the film obtained after curing is highly transparent, which makes the material suitable for both, reflection and transmission holography.