Φ1 inch Dy³⁺ and Ge⁴⁺ co-doped bismuth silicate (Bi₄Si₃O₁₂, BSO) single crystals with the length of 80–100 mm were successfully grown by Bridgman method. They are transparent, free of cracks and inclusions. The white residual at the top parts of BSO crystals disappears with co-doping 1 mol% Dy³⁺ and more than 3 mol% Ge⁴⁺. The FWHM values of X-ray rocking curves shows 1%Dy,3%Ge:BSO crystal possesses high crystallization quality. The intrinsic emission peak of BSO and the characteristic emission peaks of Dy³⁺ ions are weakened with increasing the doping concentration of Ge⁴⁺. 1 mol% Dy³⁺ and 3 mol% Ge⁴⁺ are the optimal concentrations due to high crystallization quality and moderate emission intensity. The CIE coordinates and CCT values shift towards warmer white light region with increased Ge⁴⁺ co-doping. The CCT values are close to the ideal value of 3000 K for warm white light when 1%Dy,3%Ge:BSO crystal is excited by various UV light. Increasing the temperature from 298 K to 573 K leads the luminescence lifetime to decrease from 659 μs to 645 μs. More than 95% and 80% photoluminescence intensity at room temperature is still retained at 423 K and 573 K respectively. Dy,Ge:BSO crystals are potential candidates for fabricating high power warm WLEDs.

A series of LiNbO₃ crystals doped with various MgO concentrations (0, 3%, and 5 mol%) was simultaneously grown in one furnace by the modified vertical Bridgman method. The wet chemistry method was used to prepare the polycrystalline powders, and the growth conditions were optimized. The full width at half maximum of high-resolution X-ray rocking curves for (001) reflection of 5 mol% Mg doped lithium niobate (LN) crystal was about 8″, which meant it possessed high crystalline quality. The OH⁻ absorption spectra shifted to 3534.7 cm⁻¹, and the UV absorption edge violet shift indicated that 5 mol% MgO successfully doped in LN and exceeded the threshold. The extraordinary refractive index gradient of 5 mol% Mg doped LN crystal was as small as 2.5 × 10⁻⁵/cm, which exhibited high optical homogeneity.