It was noted that Cu(I) centers in glasses produced broad-band emission in the visible range, and possible light amplification by monovalent Cu in phosphate and borate glasses was considered. The nominal composition of the phosphate glass was P2O5-16.7La2O3-16.7mol%Li2O, with a maximum Cu concentration of 2.3 x 1020/cm3. The composition of the borate glass was B2O3-25MgO-12.5mol%La2O3, with a maximum Cu concentration of 8.8 x 1019/cm3. A broad-band blue emission which peaked at about 480nm was observed in both types of glass and was attributed to single Cu+ centers. An additional orange-red fluorescence, which peaked at about 570nm, was observed only in the phosphate glasses which were richest in Cu. It was attributed to (Cu+-Cu+) pairs.

A.Jacob, C.Parent, C.Marcel, G.Le Flem, B.Moine, C.Pedrini: Materials Science Forum, 1997, 239-241, 283-6