Write-once optical disc media with large change of reflectance using copper island films

A new write-one optical disc medium using a metal island film is proposed and investigated experimentally. The reflectance and absorbance of an 8 nm thick copper island film were 49 and 37%, respectively, at a wavelength of 780 nm and the reflectance was decreased to 15% by heating the film at a temperature above 130 degrees C, which shows that it can be used as an efficient heat-mode write-once memory for commercially available laser diodes.