Writing and Erasure of Holographic Gratings in Dye-Doped Polymer Dispersed Liquid Crystals

We Demonstrate that is possible to write and erase holographic gratings in dye-doped polymer dispersed liquid crystals (PDLC). PDLC samples were irradiated after complete curing using two beams in an interferometric geometry. In this way permanent holographic gratings were written with a resolution up to 100 lines/mm. The erasure was obtained by a single beam, while successive writing were possible again by two beams interference, without any degradation after many cycles. The origin of the effect can be the onset of periodic distribution of droplets of different shape and spatial diffusion of the dye molecules.