Up-conversion fluorescence of Pr3+ ions in PbWO4 single crystal

Optical absorption spectra and site-selective fluorescence laser spectroscopy of Pr3+ in lead tungstate crystal have been investigated at temperatures from 10 to 300 K. The up-conversion emission from 3P1 and 3P0 levels following excitation of the 1D2 state has been observed for the first time in PbWO4 crystal at different temperature. The main up-conversion emission mechanism in this Pr3+-doped PbWO4 has been discussed. It is found that the up-conversion fluorescence intensity has a quadratic dependence on the laser input power. The temporal behavior of the up-converted emission indicates that an energy transfer up-conversion is the dominant mechanism in this crystal.