Improved sensitivity of dye-doped thermoplastic disks for holographic data storage

Holographic data storage materials based on dye-doped thermoplastics are currently under development. The materials are injection moldable into the standard disk format and have much lower shrinkage than photopolymer materials. Injection-molded disks with dyes from the class of o-nitrostilbenes presented acceptable capacities but a very low sensitivity. In this paper, theoretical analysis and experimental results on the sensitivity and sensitivity improvement for dye-doped thermoplastic disks are presented. Theoretical analysis shows that the quantum efficiency of the dye transformation is the key parameter for sensitivity improvement. An experimental method for measuring the quantum efficiency was developed. Dyes based on the diarylethene functionality with orders of magnitude higher quantum efficiency were identified. Sensitivities measured from the blended diarylethene/polycarbonate, injection-molded, 1.2mm thick disks showed sensitivities of ∼10–100cm∕J at both 532 and 405nm wavelengths.