Permanent polarization gratings in elastomer azo-dye systems: comparison of layered and mixed samples

An investigation was carried out of permanent polarization gratings recorded in films of polymer (elastomer) and azo dye written by two orthogonally circularly polarized Anion laser beams. The films prepared were of two kinds, namely, a mixture of dye and polymer and a layered structure, i.e., a thin polymer film covered with dye. In both samples gratings with long-time stability were observed. The layered sample had higher diffraction efficiency than the mixed sample for low writing intensities when no reliefs were present and pure polarization holograms were recorded. For higher recording intensities, reliefs were observed in both cases: The mixed sample's efficiency was much higher than that of the layered sample, suggesting that layered systems inhibit formation of reliefs. The stability of the recorded structures can be attributed to molecular interactions between polymer and dye.