FREQUENCY UPCONVERSION FLUORESCENCE OF Er3+-DOPED TeO2–WO3GLASS

摘要

Er3+-doped TeO2–WO3glass has been fabricated and characterized. Judd-Ofelt intensity parameters .t(t=2, 4, 6) were calculated by absorption spectrum and Judd-Ofelt theory and found to be .2=5.38×10–20 cm2, .4=1.78×10–20 cm2, .6=0.75×10–20 cm2. Intense green and weak red emission bands centered at 530 nm, 548 nm and 659 nm, corresponding to 2H11/2→4I15/2, 4S3/2→4I15/2and 4F9/2→4I15/2transitions of Er3+, were observed under 977 nm excitation. The dependence of upconversion intensities on excitation power presents two photon absorption processes for the three emission bands. The upconversion mechanism is discussed, and the dominant mechanisms are excited state absorption and energy transfer upconversion. The intense frequency upconversion fluorescence of Er3+-doped TeO2–WO3glass may be a potential material for developing upconversion fiber optical devices