Gordon E. Johnson

Ablative optical recording using organic dye‐in‐polymer thin films: Some mechanistic aspects

The influence of a number of materials properties and device structure variations on the energy threshold for laser marking of organic dye‐in‐polymer films has been investigated. Our results indicate that the write‐sensitivity of these organic dye‐in‐polymer optical recording media is strongly dependent on the absorption efficiency of the recording film, the quantum efficiency of generation of thermal energy by the dye and the recording film thickness for films >100 nm. The write‐sensitivity is however, not dependent on the glass transition temperature, the surface tension or the melt viscosity of the polymer binder. This independence is attributed to the very rapid nature of the mark formation process. The technological implications of the present work are discussed.

Barrier Coatings For Optical Recording Media

Metallic optical recording layers such as Te are degraded on exposure to oxygen and water. Both oxygen and moisture are necessary for the oxidation of Te to proceed at a significant rate. In this report, the feasibility of protecting thin metal layers from oxidation is examined in light of the known vapor permeability characteristics of selected organic polymeric materials. Experimental results are presented for multilayer Te structures.

Wavelength-dependent marking characteristics of AR tellurium trilayers

Characteristics and performance of a novel optical recording material in which information is recorded by surface deformation are described. This deformation recording material (DRM) has a high sensitivity (0.5 NJ/U2) independent of wavelength and adapted for use with a low-power He-Ne or diode laser. As opposed to ablative-type material, DRM type gives sharp clean reproducible recorded points free of relief rims and debris, which make possible carrier to noise ratio as high as 65 dB within 30 kHz for frequencies in the IO-15-MHz range. Repetitive readout is possible below recording threshold without alteration. DPM-type media enable direct replication of metallic copy by an electrolytic process or plastic copy by a cold moulding process. DRM media are well adapted to recording of broadcast quality video or high data rate and have good archival properties. (13 min)