PHOTOSTIMULABLE LUMINESCENCE GLASSES AS A NOVEL MATERIAL FOR OPTICAL MEMORY

We report on photostimulated luminescence in sodium borate glasses dop ed with Eu2+ (Ce3+) and Sm3+. When X-ray or 266 nm UV laser irradiated glasses were excited by a He-Nr laser (633 nm). photostimulated lumin escence at 470 nm for Eu3+-doped glass and at 360 nm for Ce3+-doped gl ass clue to the 5d-4f transition of Eu2+ and Ce3+ was observed. X-ray absorption spectra of glasses, X-ray irradiated for various durations and photostimulated excitation spectra were measured. On comparing wit h the mechanism of photostimulated luminescence in BaFBr:Eu2+, the lum inescence is proposed to have resulted from the photostimulated recomb ination of holes and electrons at traps, which leave the electrons in a long-lived excited stare. These glasses con be used as materials for read once and write many optical memories, which is considered to be important for the protection of certain types of software.