Single-beam overwrite experiment using In-Se based phase-change optical media

Single-beam overwrite in an optical disk is reported using In-Se-Tl amorphous-crystalline phase-change recording films having very short erasing (crystallization) time of 0.2 μs. The lifetime of the amorphous state in an In-Se-Tl film is estimated to be longer than 10 years at 60 °C. This is due to its high crystallization temperature (135 °C) and high activation energy (2.6 eV). The phase-change cycles can continue over 106 cycles in stationary state experiments using test samples. The possibility of single beam overwrite (rewriting without prior erasing as with a magnetic disk) is verified by using a 1.6-μm-diam round laser beam spot irradiated on a 5-in.-diam disk rotating at 2400 rpm.