Abstract
In this work we report the infrared to visible upconversion luminescence in the low phonon-energy host material KPb
2Cl
5 doped with Pr
3+ ions. A strong orange luminescence from the
1D
2 level, and less intense blue, green, and red emissions from the
3P
0,1 levels have been observed under infrared excitation inside the
1G
4 level and compared with those obtained under one photon excitation. The upconverted fluorescence from the
1D
2 level shows a quadratic dependence on the pump power indicating a two photon process, whereas the pump power dependence of the blue fluorescence from level
3P
0 is nearly cubic, which indicates a three photon mechanism. The possible excitation mechanisms responsible for these upconversion processes are discussed.