Preparation and characterization of Irgacure 784 doped photopolymers for holographic data storage at 532 nm

This paper presents the development of a thick photopolymer for holographic data storage at a wavelength of 532nm. Irgacure 784, one kind of the titanocene photoinitiators, has been selected and doped to synthesize the photopolymers in this research. Using a two-step thermo-polymerization procedure two photopolymer samples have been fabricated, Irgacure 784 doped poly(methyl methacrylate) (PMMA) and Irgacure 784 doped epoxy resin. Samples of 2mm thick have been fabricated. Holographic measurements show that Irgacure 784 doped epoxy resin is very sensitive at 532nm and that it is capable of supporting holographic data storage at a ultra-fast recording rate of 760Mbs^-1. Mass spectrum measurement, solid state ¹H-NMR spectrum measurement, and thermogravity analyses (TGA) have been performed. The results reveal the physical mechanism of holographic recording in these samples, providing a guideline for a design strategy and fabrication technique to produce a low-shrinkage recording material for holographic data storage in the tera-byte information age.