Top-seeded solution growth, spectral analysis and laser properties of a novel Nd-doped Bi2Mo2.66W0.34O12 crystal

Abstract

High-quality single crystals of new Nd-doped scheelite, Bi₂Mo_2.66W_0.34O₁₂ (Nd:BMO), with dimensions up to 80 × 57 × 35 mm³ were grown via the top-seeded solution growth (TSSG) method using a mixture of MoO₃–WO₃ as a flux for the first time. The polarized absorption and fluorescence spectra as well as the fluorescence decay curve of the crystal were investigated in detail at room temperature (RT). Comparisons between the radiative and fluorescence lifetimes indicate a high fluorescence quantum efficiency (close to unity) and, thereby, the nonradiative transition from the ⁴F_3/2 multiplet can be neglected in the laser performance. Some important spectroscopic parameters, including the effective intensity parameters for different polarizations, were calculated based on the Judd–Ofelt (JO) theory. The continuous wave (CW) laser performance at 1064 nm was demonstrated with Y- and Z-cut crystals under output coupler transmissions of 2% and 5%, respectively. A maximum output power of 113 mW was achieved under the absorbed power of 650 mW, corresponding to an optical-to-optical conversion efficiency of 17.4% and a slope efficiency of 21.6%. Considering the intrinsic high cleavability of the crystal along the (010) plane and the intense Raman activity of molybdates and tungstates, it is reasonable to expect that the Nd:BMO single crystals may have potential applications in microchips and self-stimulated Raman lasers.