Polarization holographic characteristics of TI/PMMA polymers by linearly polarized exposure

Abstract

Polarization gratings can be recorded in photo-induced anisotropic materials. Here, we examined the anisotropy of TI/PMMA (IRGACURE 784 doped polymethyl methacrylate) polymer by investigating the maximum refractive index modulation of TI/PMMA polymer due to photo-induced birefringence which reached 9.06 × 10−5. Based on the linearly polarized light theory, the diffraction efficiency and polarization direction of the diffracted grating in TI/PMMAs were investigated with two different polarized incident beams. When the polarization angle difference between two incident beams increased from zero to π/2, the diffraction efficiency gradually decreased, while the polarization direction of the diffracted beam was different from that of recording beam. When the angle difference of polarization between two incident beams was π/2, namely, orthogonal polarization recording, the polarization direction of diffracted grating would be consistent with that of recording beam. In the case of orthogonal polarization recording, the diffraction efficiency of 1–3 mm TI/PMMA polymer was obtained by 5%, 12% and 16%, respectively. In the experiment, when the intersection angle difference between two incident beams was π/2, the polarization multiplexing storage of TI/PMMA polymer was realized with the dynamic range in 1–3 mm samples of 0.16, 0.22 and 0.26 by orthogonal polarization recording, respectively. The angular and polarization multiplexing storage of holographic grating was realized in TI/PMMAs. The research on polarization holographic storage could provide the experimental basis and feasibility for multi-dimensional multiplexing storage in TI/PMMA polymer.