Preparation and up-conversion luminescence of Er-doped yttria stabilized zirconia single crystals

High-quality yttria-stabilized zirconia (YSZ) single crystals doped with different concentrations of Er 2 O 3 were grown by the optical floating zone method . The cubic phase of ZrO 2 was retained when Er 3+ partially replaced Y 3+ in the YSZ matrix. Up-conversion luminescence was observed when the crystals were excited by a 980 nm laser diode . The optical power curve was obtained by plotting the up-conversion luminescence intensity against the laser power, and both the green and red light up-conversion were shown to involve two photons. Seven characteristic visible and three infrared absorption peaks were observed in the absorption spectrum of the 1.50 mol% Er 2 O 3 : YSZ. The up-conversion spectra produced three prominent peaks at 547(green), 561 (green) and 679 (red) nm. Green and red light maxima were observed with Er 2 O 3 concentrations of 1.5 mol% and 0.5 mol%, respectively. Oscillator strength parameters Ω t (t = 2, 4, 6) were determined using the Judd-Ofelt theory and Ω 2  = 9.90 × 10 −20  cm 2 , Ω 4  = 2.92 × 10 −20  cm 2 , Ω 6  = 3.32 × 10 −20  cm 2 . The Ω 4 /Ω 6 ratio (0.88), which is the key parameter for laser performance of reactive matrix materials , indicates that Er 3+ -doped YSZ has potential laser applications.