Holographic data storage has large storage capacity and high transfer rate, it becomes one of the next-generation information storage technologies. Bis(2,6-difluoro-3-(1-hydropyrrol-1-yl)phenyl)titanocene (IRG 784) is a good photoinitiator doped in photopolymer, poly(methyl methacrylate) （PMMA）is an excellent choice to making photopolymer with thickness of millimeter range. The solubility of phenanthrenequinone in MMA is a little low, for IRG 784 is very high. In this paper, I use IRG 784 as photoinitiator doped in PMMA made a kind of photopolymer with thickness of millimeter range for holographic data storage. We studied the optical characteristics of IRG 784–doped PMMA photopolymer with different weight ratio of IRG 784 doped.
For the preparation of material, we use methyl methacrylate solution as the monomer, azo-bis-isobutyronitrile as the thermo-initiator. The samples with clear optical transmission is orangered. The wavelength of laser for recording and reconstructing we used was 532nm. In the recording process, recording waves interfered for 2 seconds with the cross angle of 60 degrees. After 2 seconds is the reconstruction process, the original reference wave reconstructed the grating for 0.6 seconds. These two processes cycled until the reaction ended. We set the polarization state of signal wave as s-polarization. Both s-polarization and p-polarization as reference wave we used to recording.
Through a series of experiments, we can conclude that the weight ratio of IRG 784 dissolved in MMA is significant to increase diffraction efficiency. Although the diffraction efficiency is lower than in traditional holography, our material can be used in polarization holography.