Fabrication and luminescent properties of holmium doped Y2Zr2O7 transparent ceramics as new type laser material

Via a vacuum sintering method, highly transparent Ho: Y2Zr2O7 ceramics with different holmium doping concentrations were successfully fabricated for the first time. Y1.99Ho0.01Zr2O7 and Y1.98Ho0.02Zr2O7 transparent ceramics exhibit the highest in-line transmittance at 72% in the visible (Vis) region and over 75% in the near infrared (NIR) region. The microstructure and crystal structure of Ho: Y2Zr2O7 transparent ceramics were fully investigated by SEM and XRD measurements. Photoluminescence spectra demonstrated that Ho: Y2Zr2O7 ceramics can be effectively excited at 376 nm and 460 nm. Strong green (centered at 551 nm) and NIR (centered at 1111 nm) emissions were observed in the downshifting (DS) luminescence. Meanwhile, same green emissions have been observed in the upconversion (UC) luminescence. The luminescence decay curves have also been studied, demonstrating that the longest average fluorescence lifetime of Ho: Y2Zr2O7 transparent ceramics reaches 48 mu s. Combined with the high temperature resistance and good mechanical strength of Y2Zr2O7 transparent ceramics, these results suggest that Ho3+: Y2Zr2O7 transparent ceramics are able to generates both down and up converted fluorescence.