Highly efficiency up and down -conversion photoluminescence in Er/Tm/Yb co-doped lutecia-stabilized zirconia single crystals

Abstract

High-quality transparent cubic lutecia-stabilized zirconia and LSZ:Yb1Er0.05Tm0.5 single crystals were grown by the optical floating zone method for the first time. For comparison, YSZ and YSZ:Yb1Er0.05Tm0.5 single crystals were also grown. No absorption peaks were observed in the 200 ∼1100 nm range in the transmission and absorption spectra of LSZ and YSZ, indicating that both crystals are excellent matrix crystals. The absorption spectra of LSZ:Yb1Er0.05Tm0.5 and YSZ:Yb1Er0.05Tm0.5 crystals exhibit several absorption peaks at 377, 408, 462, 488, 516, 679, 785 nm and a strong broad absorption band in the 836 ∼ 1050 nm range. The up-conversion photoluminescence of the LSZ:Yb1Er0.05Tm0.5 crystal excited by a 980 nm laser exhibited several distinct emission peaks at 300, 372, 476, 531, 548, 642 and 798 nm; similar emission peaks were observed in the up-conversion photoluminescence spectrum of the YSZ:Yb1Er0.05Tm0.5 crystal, except for the absence of the 300 nm peak. The intensity of the emission peaks of the former was higher than that of the corresponding peaks of the latter. Power curves indicated that the 300 nm emission is a four-photon up-conversion process, the 372 nm and 476 nm emissions are three-photon processes, and the 548 nm and 642 nm emissions are two-photon processes. Under excitation at 379 nm, the down-conversion photoluminescence spectra of the LSZ:Yb1Er0.05Tm0.5 and YSZ:Yb1Er0.05Tm0.5 crystals showed emission peaks at 450, 457, 511, 531 and 637 nm, the peak intensities of the former are higher than those of the latter, which is due to the former with higher density and lower phonon energy as compare to the latter. These results indicate that LSZ:Yb1Er0.05Tm0.5 single crystal has advantages over YSZ:Yb1Er0.05Tm0.5 single crystal for luminescence in photonic devices.