Growth And Spectral Properties Of Nd: Ca_xY_1-xVO₄ Crystals

This article reports the systemic investigation of materials synthesis, crystal growth, parameters and spectral properties about Nd:CaxY1-xVO4 crystals.The materials were synthesized by the liquid-phase reaction method and state-phase method. Different Ca²⁺-doped and Nd³⁺-doped Nd:CaxY1-xVO4 crystals were grown by Czochralski, and growth technique of the crystals was explored. The concentration and the segregation coefficients of the doped ions in Nd:CaxY1-xVO4 crystals were detected and calculated. The mean value of segregation coefficients about Ca²⁺ ions and Nd³⁺ ions are 0.52 and 0.61 respectively. The lattice parameters were calculated, and XRD analysis showed that the Nd:CaxY1-xVO4 crystals also belonged to tetragonal system and had Zircon-Type structure. The thermal conductivity of CaxY1-xVO4 crystal was measured. The result indicated that substituting Ca²⁺ in YVO4 crystal made the thermal conductivity increase.The Raman spectra, absorption spectra, fluorescence spectra, fluorescent decay curves of the crystals were measured at room temperature. The factor group symmetry analysis method was used to analyze the Raman spectra of CaxY1-xVO4 crystals, and all the Raman peaks were assigned on the basis of the group theory. The result indicated that substituting Ca²⁺ in YVO4 crystal made the intensity of VO4 Raman peak at 893cm-1 markedly enhance. According to Judd-Ofelt theory, the spectra parameters of Nd:CaxY1-xVO4 crystals were calculated. The absorption cross-section of 1.21at.%Nd³⁺-doped Ca0.05Y0.95VO4 crystal was calculated as 14.11×10-20cm2 at 808nm, so the crystal was fit to be pumped by 808nm LD, and its emission cross-section and radiation lifetime were calculated as 2.771×10-18cm2 and 106.5μs respectively. In a word, after substituting Ca²⁺ in Nd:YVO4 crystal, the laser performance of the crystal didn't change a lot, and it also possibly realized laser output. However, its Raman performance was improved, so Nd:Ca0.05Y0.95VO4 crystal was expected to be a kind of multiplex material of laser crystal and Raman crystal.