Role of Er3+ concentration in spectroscopic and laser performance of CaYAlO4 crystal

Three heavily Er3+-doped caYAlO(4) single crystals were successfully grown by Czochralski method. The emission spectra and the fluorescence decay curves have been recorded at room temperature. A combination of experimental data, rate equation and Dexter theory are used to investigate the influence of Er3+ doping concentration on the spectra character and the inner cross relaxation of Er3+:CaYAlO4 crystal. Results show that the self terminate effect of the transition I-4(11/2) -> I-4(13/2) can be suppressed by heavy Er(3+)doping. But if the doping concentration goes too high, the much larger cross relaxation coefficient of I-4(11/2) level than that of I-4(13/2) level would results in the increase of up-conversion emission and the quench of near and mid infrared emission. The laser performance was also studied. The maximum output power of 225 mW at 2733 nm was acquired with an optical conversion efficiency of 14.9%. (C) 2015 Elsevier B.V. All rights reserved.