Optimal period for diffraction gratings recorded in polymer dispersed liquid crystals

New diffusion model of recording diffraction gratings in the media of PDLC is described in which besides diffusion of monomer molecules also diffusion of polymer molecules and non-locality of diffusion coefficient are taken into account. It lets us to explain why diffraction efficiency is low for low and high values of intensities of grating recording beam. With the considered model, we have theoretically got optimal period for grating recording.