Visible Upconversion Luminescence from Y2O3:Eu3+,Yb3+

A red upconverted emission is reported for yttria codoped with Eu3+ and Yb3+ upon excitation by a 970 nm laser diode. The concentration dependence and temperature dependence down to 10 K of the upconverted emission have been investigated. Two alternative models are presented to simulate the emission intensity-temperature dependence.