HOST-DEPENDENT OPTICAL-TRANSITIONS OF ER3-GERMANATE AND LEAD-TELLURIUM-GERMANATE GLASSES( IONS IN LEAD)

Differential scanning calorimetry, Raman scattering, optical absorptio n, and upconversion of infrared to green luminescence have been studie d for Er3+-doped lead-germanate glass 55GeO(2) . 20PbO . 10BaO . 10ZnO . 5K(2)O (GPBZK) and lead-tellurium-germanate glass 30GeO(2) . 30PbO . 30TeO(2) . 10CaO (GPTC). Judd-Ofelt intensity parameters of Er3+ in the two host glasses were determined and used to calculate radiative t ransition rates and lifetimes. Values of the radiative quantum yield o f the S-4(3/2)-->I-4(15/2) transition and the infrared (797 nm) to gre en (547 nm) upconversion efficiency of Er3+ Were obtained. It has been found that the S-4(3/2)-->I-4(15/2) radiative transition rate of Er3 in GPTC glass is about twice that in the GPBZK glass and the upconver sion efficiency in the GPTC glass is about four times larger than that in the GPBZK glass. These host-dependent properties are mainly attrib uted to the enhanced local field and the reduced multiphonon rate in l ead-tellurium-germanate glass compared to lead-germanate glass. (C) 19 96 American Institute of Physics.