REWRITABLE OPTICAL-DISK FABRICATION WITH AN OPTICAL-RECORDING MATERIAL MADE OF NAPHTHALOCYANINE AND POLYTHIOPHENE

A novel rewritable optical disk that uses an optical recording materia l made of naphthalocyanine and polythiophene as the recording layer is described. In this system the complex refractive index of the recordi ng material changes reversibly, depending on the aggregation states of naphthalocyanine induced by a conformation change of the polythiophen e matrix. After recording, the imaginary part of the refractive index of the recording material increases to three times that of the unrecor ded part, at a wavelength of 790 nm at which a semiconductor laser emi ts light. The fabricated polythiophene/naphthalocyanine optical disk s hows a high reflectivity of 58% and a large readout modulation amplitu de (I-ll/I-top) of 0.63. It is confirmed that the polythiophene/naphth alocyanine optical disk can be played back on conventional compact-dis c players even after ten cycles of rewriting. (C) 1995 Optical Society of America