Analysis of monomer diffusion in depth in photopolymer materials

Monomer diffusion plays an important role in the process of hologram formation in photopolymer materials. The gradient of monomer generated during the recording process origins a motion of the monomer molecules from the dark to the bright zones. The high physical thickness of photopolymers required to use them as holographic memories implies an additional gradient of monomer in depth. The exposure time needed to record a single hologram is very short; nevertheless if many holograms are multiplexed an exposure time around 100 s or more is required. For this long period the importance of monomer diffusion in depth must be studied. Other important factor in order to design an experimental schedule is the time needed between two consecutive holograms. In this work we analyze the importance of the monomer diffusion in depth in these cases using a three-dimensional diffusion model solved using a finite differences method.