A noncentrosymmetric (NCS) compound, MgTeMoO₆, has been synthesized using the high temperature solution method with TeO₂–MoO₃ mixture as a flux. MgTeMoO₆ crystalizes in the orthorhombic space group P2₁2₁2 (No. 18) with cell parameters a = 5.03780(10) Å, b = 5.26910(10) Å, c = 8.8985(2) Å, and Z = 2. The compound exhibits a novel neutral layered structure consisting of asymmetric MgO₆ octahedra, TeO₄ polyhedra and MoO₄ tetrahedra. Thermal stability measurements revealed an incongruent melting point of 682.35 °C. The crystal exhibits a very broad transmission range from 360 nm to 5.2 μm. Powder second-harmonic generation (SHG) measurements using 1064 nm radiation indicates that the crystal exhibits a strong SHG efficiency of ∼1.5 × KTiOPO₄. Additional SHG measurements indicate the material is type-I phase-matchable. Furthermore, calculations on the local dipole moment indicates that the strong SHG response of MgTeMoO₆ is mainly caused by the three types of NLO-active units (TeO₄, MoO₄ and MgO₆).

Bulk single crystals of α-BaTeMo₂O₉ with dimensions up to 51 × 30 × 20 mm³ were grown successfully by a top-seeded solution growth (TSSG) method using TeO₂-MoO₃ mixture as a flux. High-resolution X-ray diffraction measurement on the (400)-faced plate indicates that the full-width at half-maximum (FWHM) of the rocking curve is 16.55′′. The as-grown crystal exhibits {010}, {002}, {110}, {111} and {201} facets, which are in good accordance with the predicted growth morphology based upon the Bravais-Friedel and Donnay-Harker (BFDH) method. In addition, thermal properties including thermal expansion, specific heat, thermal diffusivity and thermal conductivity were investigated as a function of temperature. The average linear thermal expansion coefficients along the a-, b-, and c-axis from 30 °C to 500 °C were measured to be α_a = 9.10 × 10⁻⁶ K⁻¹, α_b = 19.58 × 10⁻⁶ K⁻¹ and α_c = 11.94 × 10⁻⁶ K⁻¹, respectively. The specific heat was measured to be 0.433–0.566 J (g K)⁻¹ over the temperature range of 30–540 °C. The thermal conductivity along the a-axis is larger than those along other directions (κ_a>κ_b> κ_c). The transmission spectra and refractive indices were also measured. The α-BaTeMo₂O₉ crystal exhibits a wide transmission window ranging from 380 nm to 5530 nm. The large birefringence of α-BaTeMo₂O₉ (Δn = 0.305 for light at 404.7 nm) indicates that it is not only Type I and II phase-matchable, but also a very promising candidate for optical devices.

The Tm:CaF₂ single-crystal fibers were successfully grown by modified temperature gradient technique method. The J-O intensity parameters, spontaneous radiative transition rates, radiative lifetimes and fluorescence branching ratios of Tm³⁺ were calculated with Judd-Ofelt theory. A systematic study of the fluorescence characteristics has been carried out. Simulated emission cross-sections of the ³F₄ → ³H₆ transition were calculated to be 6.68×10⁻²¹ cm⁻² and 4.65×10⁻²¹cm⁻² for crystal doped with 3 at.% and 4 at.% Tm³⁺. The 64.4% slope efficiency with output power of 2.23W was achieved in 3 at.% Tm:CaF₂ single-crystal fiber. The slope efficiency decreased to 44.5% and maximum output power decreased to 1.65W in 4 at.% Tm:CaF₂ single-crystal fiber. Obtained results show that Tm-doped CaF₂ single-crystal fibers are promising materials for IR laser action generation.

A new polymorph of BaTeW2O9 with space group Pnma was identified during the exploration of the BaO-WO3–TeO2 system. Single-crystal X-ray diffraction measurements show that the material exhibits a 3D tunnel structure consisting of W–O6 octahedra connected with Te–O3 tetrahedra. Bulk single crystals of orthorhombic BaTeW2O9 with dimensions of 24 mm × 22 mm × 15 mm were grown by a top-seeded solution growth (TSSG) method using TeO2 as flux. Theoretical morphology of the crystal was obtained using the Bravais–Friedel and Donnay–Harker methods for comparison. The crystal shows a high transmittance from 360 nm to 5 μm as well as large birefringence (with Δn = 0.247 at 404.7 nm). The Raman spectrum shows that there is a Raman shift with high intensity and narrow peak width at 910.93 cm−1. TGA and DSC analysis indicate that the material melts incongruently at 783 °C. The thermal conductivity of the crystal was measured to be 1.23, 2.61 and 0.95 W m−1 K−1 at 50 °C along the a-, b- and c-axes, respectively.