Up-conversion luminescence of Er3+/Yb3+/Nd3+-codoped tellurite glasses

Up-conversion luminescence and energy transfer (ET) processes in Nd3+–Yb3+–Er3+ triply doped TeO2–ZnO–Na2O glasses have been studied under 800 nm excitation. Intense green up-conversion emissions around 549 nm, which can be attributed to the Er3+: 4S3/2→4I15/2 transition, are observed in triply doped samples. In contrast, the green emissions are hardly observed in Er3+ singly doped and Er3+–Yb3+ codoped samples under the same condition. Up-conversion luminescence intensity exhibits dependence of Yb2O3-concentration and Nd2O3-concentration. Up-conversion mechanism in the triply doped glasses under 800 nm pump is discussed by analyzing the ET among Nd3+, Yb3+ and Er3+. And a possible up-conversion mechanism based on sequential ET from Nd3+ to Er3+ through Yb3+ is proposed for green and red up-conversion emission processes.