Measurement of permanent vectorial photoinduced anisotropy in azo-dye-doped photoresist using polarization holography

In this paper, we reveal properties of a new optical material, which consists of a laboratory photoresist doped with Disperse Red 1 azo-dye molecules. First, we describe briefly the material that we developed and its physical behaviour. Then, we give the empirical results that we obtained on the photoinduced anisotropy (dichroism and birefringence) of the material. We observed a reorientation of azo-dye centres and, then, a permanent and non-reversible fixing of the optically induced orientation of the dyes by the cross-linking of the photopolymer. Finally, we measured a permanent vectorial photoinduced anisotropy persisting over more than 65 days, by using a holographic polarization grating generated from the interference between two orthogonal left and right circularly polarized beams.