OPTICAL-TRANSITIONS OF ER3-TELLURIUM-GERMANATE GLASSES( IN LEAD)

Optical-absorption, photoluminescence, and up-conversion luminescence were measured for Er3+ in lead-tellurium-germanate glasses (63-x)GeO2. x-TeO2.27PbO.10CaO with x = 0, 10, 20, 30, and 40. Each glass sample c ontains an extra 0.2 mol% Er2O3. Judd-Ofelt intensity parameters were determined and used to calculate the radiative transition rates and li fetimes of Er3+ in glasses with different TeO2 content. It has been fo und that the S-4(3/2) --> I-4(15/2) radiative transition rate and the infrared (800 nm) to green (547 nm) up-conversion efficiency of Er3+ i ncrease with increasing TeO2 content. Our results indicate that incorp orating TeO2 up to 40 mol% into a lead-germanate glass network increas es the luminescence efficiency due to the increased refractive index a nd decreased maximum phonon energy of the host glass.