Growth, thermal and laser properties of neodymium-doped sodium yttrium double tungstate crystal

In this paper, the neodymium-doped sodium yttrium double tungstate crystal [Nd:NaY(WO₄)₂, designed as Nd:NYW] has been grown by the Czochralski method. The data of thermal expansion and specific heat of the crystal have been measured. The thermal expansion coefficients along X and Z direction are α₁ = 3.5 × 10^-6/K and α₂ = 1.77 × 10^-5/K, respectively. The specific heat is 0.5132 J/g·K. The measured absorption spectra around 800 nm at room temperature show that the crystal has different absorption peaks, 801.25 nm for π polarization and two peaks 804.04 nm and 812.26 nm for σ polarization. The peak absorption coefficients are 9.37 cm^-1 (π) and 3.95 cm^-1 (σ at 804.04 nm). The fluorescence at room temperature show that the strongest fluorescence is centered at 1060.12 nm. The laser at 1060 nm is demonstrated pumped by a Ti:sapphire laser at 801 nm. The slope efficiency is 38.1%.