Temporal and non-ideal behavior in photopolymers

The inclusion of a nonlocal spatial response function in the Nonlocal Polymer Driven Diffusion model (NPDD) has been shown to predict high spatial frequency cut-off in photopolymers and more recently it has been shown that use of the nonlocal model is necessary to accurately predict higher order grating components. Here the nature of the temporal response of photopolymer is discussed and a nonlocal temporal response function proposed. The extended model is then solved using a finite element technique and the results discussed. Based on this model we examine the nature of grating evolution when illumination is stopped during the grating recording process. Refractive indices of the components of the photopolymer material used are determined and predictions of the temporal evolution of the refractive index modulation described. Material parameters are then extracted based on fits to experimental data for non-linear and both ideal and non-ideal kinetic models.