Polarisation-sensitive holographic recording in polyimide-containing azo-dye

Holographic recording of diffraction gratings in high Tg polyimide doped with an azo-dye Disperse Red 1 (DR1) is reported. The recording mechanism performed by laser light within the dye absorption range (632.8 and 532 nm) is due to photo-induced anisotropy in which light induced repeated trans–cis photoisomerisation of DR1 molecules leads, after many steps, to quasi-stable molecular reorientation. The characteristics of gratings recorded by two mutually parallel polarisation beams as well as orthogonal linear polarisation beams (so-called polarisation holographic gratings) were measured via observation of a light self-diffraction process as a function of many experimental parameters.