[2] Xu W, Denis J P, Ozen G,et al. The up-conversion emission of glass ceramics doped with Er3+ ions and co-doped with Er3+ and Yb3+ ions upon 650nm excitation, Phys.Stat.Sol.A, 1993,139: 503 -511

[4] Rodriguez V D, Matin I R, Alcala R, et al. Optical properties and cross relaxation among Sm3+ ions in fluorzincate glasses， J.Lumin., 1992,54:231-236

[5] Stake R, Frobel P, Barner K. Fluorescence of Sm3+ in Sm/Cu-co doped (Li2B4O7)1-x(WO3)x glasses,J.Lumin.,1993,55:115-123

[6] Naab J, Wollenhaupt M, Ahren H, et al. The fluorescence of Sm3+ in lithium molybdate borate glasses， J.Lumin.,1994,62: 9 5-100

[8] Dieke G H. Spectra and Energy Levels of Rare Earth Ions in Crysta ls. New York: Interscience Publishers,1968: 236