Growth, thermal and laser properties of Yb:YxLu1−xVO4 mixed crystal

Abstract

New mixed crystal of Yb: Y0.78Lu0.22VO4 with Yb ion concentration of 0.3 at% was grown by Czochralski method. Transmission synchrotron X-ray topography implies that this mixed crystal follows a rotational growth pattern. Crystal structure of this crystal was determined by X-ray diffraction. It showed that this crystal possesses a tetragonal zircon structure (ZrSiO4, space group I41/amd), as YVO4 and LuVO4 do. Thermal properties of this crystal were characterized by measuring its specific heat, thermal expansion coefficients and thermal conductivities. The specific heat was determined to be 0.500 J g−1 K−1 at 293 K. The average linear thermal expansion coefficients were calculated to be α11 = 1.73 × 10−6 K−1 and α33 = 9.43 × 10−6 K−1, over the temperature range of 300–777 K. The thermal conductivities were calculated to be κ11 = 5.47 W m−1 K−1 and κ33 = 6.64 W m−1 K−1 at 303 K. Continuous-wave (cw) laser test on Yb: Y0.78Lu0.22VO4 was conducted at room temperature in the wavelength range of 1035.7–1048.3 nm, and a 13.5% optical-to-optical efficiency was achieved. The good thermal properties of Yb:Y0.78Lu0.22VO4 mixed crystal and its attractive cw laser performance make it very suitable for practical applications.