Investigation Of Growth And Spectral Properties Of Yb: M_xGd_1-xVO₄ Single Crystals

The development of practical and efficient Raman laser crystal is a focus in the stimulated Raman scattering at present. This thesis attempted to influence the Raman properties of GdVO₄ single crystals by doping Sr²⁺. Meanwhile, the feasibility of M²⁺ (Ca²⁺, Sr²⁺)-doped Yb: GdVO₄ crystal used for self-Raman laser crystal was discussed.In this paper, the polycrystalline materials were synthesized by the liquid-phase reaction method and the solid-phase reaction method. And the synthesized raw materials were detected by in FTIR, differential thermal gravimetric analysis, X-ray powder diffraction method, respectively. A series of Yb: M_xGd_1-xVO₄ single crystals with different Yb³⁺ concentrations were grown by Czochralski method at pulling rate of 0.5mm/h. The Yb³⁺ and Sr²⁺ concentrations in M_xGd_1-xVO₄ crystal were obtained by ICP-AES method. The segregation coefficient of Sr²⁺ and Yb³⁺ was 0.20⁰.51 and 0.62⁰.79, respectively. The vanadium oxides, thermal expansion coefficient and the thermal conductivity was measured and analyzed.Absorption spectra and fluorescence spectra of Yb: M_xGd_1-xVO₄ crysstals were measured at room temperature, from which the Stark levels of Yb³⁺ were concluded.σabs,σem.Ï„f and Imin parameters of these crystals can be calculated according to the method of reciprocity and the F-L formula. The valueσem.Ï„f of 7.01at% Yb: Sr0.02Gd0.98VO₄ crystal is equal to 3.20×10-23cm2·s,Imin is 1.56 kW/cm2. The valueσem.Ï„f of 4.03at% Yb: Ca0.1Gd0.9VO₄ crystal is equal to 3.5610-23cm2·s, Imin is 1.49kW/cm2. The spectral parameters of Yb³⁺, Er³⁺: Ca0.1Gd0.9VO₄ crystal can be calculated according to the J-O theory. And the upconversion laser and luminous of Ca0.1Gd0.9VO₄ crystal doped with Yb³⁺, Er³⁺ in composition is discussed. The Raman spectra of Yb: M_xGd_1-xVO₄ were measured at room temperature, and all Raman peaks of Sr_xGd_1-xVO₄ crystal were assigned on the basis of the group theory. The influence of M²⁺ concentration on microstructure and the Raman gain coefficient of M_xGd_1-xVO₄ crystals were discussed.