Abstract: With the development of high-power solid-state lasers and fiber lasers, the demand for optical isolators in the visible and near-infrared regions is gradually increasing. At present, equipment components are tending towards miniaturization. The most widely used terbium gallium garnet (TGG) crystal in industry cannot meet the needs of future high-power lasers due to its small Verdet constant. Tb₂O₃ has a high Verdet constant, but its high melting point and phase transition mechanism make it difficult to achieve single crystals by Czochralski. The crystal growth of (Tb_xY_1-x)₂O₃ at different doping concentrations was explored by doping Y₂O₃ into Tb₂O₃ in this study. When the ratio of n(Tb)∶n(Y) was 1∶1, TbYO₃ single crystals were grown by laser floating zone (LFZ) method, while undoped Tb₂O₃ and (Tb_0.3Y_0.7)₂O₃ single crystals cannot be synthesized by this method. The TbYO₃ crystal has high Verdet constants (529 rad·T^-1·m^-1 at 445 nm and 116 rad·T^-1·m^-1 at 880 nm), which is 1.51 to 2.37 times that of terbium gallium garnet (TGG) crystal (350 rad·T^-1·m^-1 at 445 nm and 49 rad·T^-1·m^-1 at 880 nm). Therefore, the TbYO₃ crystal can effectively reduce the medium length for constructing optical isolators or decrease the magnetic field intensity required for embedding optical isolators. In addition, TbYO₃ crystal also has a moderate thermal conductivity of 11 W·m^-1·K^-1 and a high laser induced damage threshold of 1.67 GW·cm^-2. These advantages make TbYO₃ crystal an attractive magneto-optical material.

Key words: TbYO₃, laser floating zone method, Verdet constant, thermal conductivity, magneto-optical crystal, laser induced damage threshold