Growth And Spectroscopic Properties Of Yb - Doped Yutanium Phosphate Series Crystals

In this paper, LuPO4, YPO4 and LuxY1-x PO4 crystals doped Yb3+ions with different concentration were grown by spontaneously nucleated high-temperature solution method using lead pyrophosphate(Pb2P2O7) as the solvent. The structure and specific heats of the crystals were characterized, and the spectral properties were studied. The lasing experiments were operated on the crystals.The method, apparatus and process of crystal growth were introduced. The raw material of the solvent lead hydrogen phosphate(PbHPO4) was prepared, then mixed with rare earth oxides stoichiometrically. The bar-like and plate-like crystals of Yb:LuPO4, Yb:YPO4 and Yb:LuxY1-x PO4 were successfully grown by spontaneously nucleated high-temperature solution method.The formation mechanisms of both bar-like and plate-like crystals were analyzed by Periodic bond chain theory. The RE-element compositions of Yb:LuxY1-xPO4 crystal were determined by electron microprobe analysis. The X-ray powder diffraction patterns of the mixed crystals were recorded at room temperature by Bruker D8 Advance type diffractometer. The diffraction peaks of Yb:LuxY1-xPO4 crystal were analyzed, and the unit-cell parameters were calculated. The specific heats of Yb:Lu PO4 and Yb:Lux Y1-xPO4 crystals were measured by NETZSCH LFA 447 Nanoflash differential scanning calorimeter, respectively. The results were compared with some Yb-doped vanadate crystals.The spectral properties of the crystals were studied at room temperature. The absorption spectra of 5 at% Yb-doped LuPO4, YPO4 and LuxY1-xPO4 crystals were measured by Cary500 UV-VIS-NIR spectrophotometer, and the absorption cross-sections of the crystals were calculated, respectively. The fluorescence spectra of 5 at% Yb:LuxY1-xPO4 crystals was measured by HORIBA FluoroMax-4fluorescence spectrometer, and the emission cross-sections and fluorescent lifetime were calculated, respectively.The lasing experiments were operated using 10 at% Yb-doped LuPO4 crystal as the gain medium, the continuous-wave laser outputs were obtained. The optical-to-optical efficiencies for different output couplings were compared as well as the emission spectra measured at same output power.