The upconversion emission of Er~(3+) doped 20PbF_2-20GaF_3-15InF_3-20CdF_2-15ZnF_2-10SnF_2 glasses

• 掺Er~(3+)的20PbF_2-20GaF_3-15InF_3-20CdF_2-15ZnF_2-10SnF_2玻璃系统的上转换发光性质研究