Optical and recording properties of short wavelength optical storage materials

Research interests in short wavelength optical storage have been growing considerably in recent years. In this paper, we first present a brief introduction to the materials requirements for short wavelength optical storage and basic considerations on the relation between reflectivity and optical constants of the materials, and then report our experimental results on the optical and short wavelength recording properties of the azo dye and the phase change compounds, Ge2Sb2Te5 and Ag8In14Sb55Te23. The reflectivity contrast due to optical recording at 514.5 nm in the dye-polymer film is as high as 25%. The change in n and k of the phase change materials due to heat treatment can cause reasonably high reflectivity change at 500 nm, writing and erasing at 514.5 nm result in moderate reflectivity contrast. These suggest that the materials can be used for short wavelength optical storage.