Rare-earth ion doped lead- and cadmium-free bismuthate glasses

Rare-earth ion doped bismuthate (LZBB) glasses without traditional glass formers, lead and cadmium, have been attempted to prepare. In Er3+ doped LKBB glass system, Judd-Ofelt parameters ω2, ω4, and ω6 have been derived to be 3.48× 10-20, 9.47× 10-21, and 1.01× 10-20 cm2, respectively, which shows a medium symmetry of the ligand field in the site occupied by Er3+ and a less covalent environment of Er3+. Effective 1.53 μm fluorescence was recorded and the peak emission cross section is proved to be more than 9.0× 10-21 cm2, which is much higher than those in phosphate, silicate, germanate, and tellurite glasses and beneficial to achieving powerful stimulated emission of Er3+ in LZBB glass system. Pr3+, Tm3+, and Ho3+ doped LZBB glasses with the maximum phonon energy of only ∼600 cm-1 are potential candidates for developing O -, S -, and U -band amplifiers and medical lasers.