Chromium—rare-earth energy transfer in YAlO3

Energy transfer between chromium and rare-earth ions in YAlO3 was investigated from fluorescence excitation spectra and fluorescence decay studies. Rare earths examined include Nd3+, Ho3+, Er3+, Tm3+, and Yb3+. Chromium—to—rare-earth transfer was observed in all cases; evidence of rare-earth—to—chromium transfer was also observed for Ho3+. Phonon-assisted transfer rates are dependent on the energy mismatch of the transitions for the two ions involved. The efficiency of the Cr3+ → Nd3+ energy transfer in YAlO3 was measured at 300°K and found to be greater than in Y3Al5O12 for comparable dopant concentrations. Use of chromium as a sensitizer for rare-earth fluorescence and laser action is discussed.