Thermal properties and CW laser performances of pure and Nd doped Bi2ZnB2O7 single crystals

Abstract

Centimeter-sized Bi₂ZnB₂O₇ (BZBO) and Nd:Bi₂ZnB₂O₇ (Nd:BZBO) single crystals are grown using the Kyropoulos method. The thermal properties and continuous wave (CW) laser performance are investigated. Results show that the BZBO crystal possesses moderate specific heat (0.62 J g⁻¹ K⁻¹ at 20 °C), small thermal expansion (α₁₁ = 6.9 × 10⁻⁶ K⁻¹, α₂₂ = 11.2 × 10⁻⁶ K⁻¹ and α₃₃ = 1.9 × 10⁻⁶ K⁻¹ at 20 °C) and large thermal conductivities (4.3, 3.2 and 4.0 W m⁻¹ K⁻¹ along the crystallographic a-, b- and c-axes at 25 °C, respectively). Moreover, the CW laser tests are realized at a wavelength of 1.06 μm for the Nd:BZBO crystal (0.5 mol% Nd³⁺), and the output powers are found to be around 256 mW, 235 mW and 312 mW along the optical X-, Y- and Z-orientations, respectively. Nd:BZBO might be another kind of important laser and nonlinear optical crystal in the oxyborate family.