Rare earth garnet (R₃Fe₅O₁₂, RIG) single crystals are the most ideal magneto-optical medium for optical isolators for wavelength longer than 1.1 μm, which has been commercially used in optical fiber communications. However, it is still a great challenge to grow large size RIG single crystals. In this work, high-quality Y₃Fe₅O₁₂ (YIG) and Bi_0.9Tb_2.1Fe₅O₁₂ (Bi:TIG) single crystals were successfully grown by the flux–Bridgman method for the first time. The as-grown crystals up to 20 mm in diameter was obtained using the PbO–B₂O₃ flux. The transmittance of YIG crystals is over 75% in the region of 1100–2500 nm. TIG crystals also have good transmittance in the range of 1100–1700 nm, and show typical Tb absorption from 1700 to 2500 nm. The specific Faraday rotations of YIG and Bi_0.9Tb_2.1Fe₅O₁₂ crystals are 185 (°)/cm and –1250 (°)/cm at 1550 nm, which are comparable to the commercial RIG crystals grown by LPE method. The present results indicate that flux–Bridgman method shows great potential to grow large size and high-quality RIG magneto-optical crystals.

稀土石榴石（R ₃ Fe ₅ O ₁₂，RIG）单晶是波长大于1.1 μm的光隔离器最理想的磁光介质，已在光纤通信中得到商业应用。然而，生长大尺寸RIG单晶仍然是一个巨大的挑战。在这项工作中，高质量的 Y ₃ Fe ₅ O ₁₂ (YIG) 和 Bi _0.9 Tb _2.1 Fe ₅ O ₁₂ (Bi:TIG) 单晶首次通过助熔剂-布里奇曼法成功生长。使用 PbO–B ₂ O ₃获得直径达 20 mm 的生长晶体通量。YIG 晶体在 1100-2500 nm 范围内的透射率超过 75%。TIG 晶体在 1100-1700 nm 范围内也具有良好的透射率，并在 1700-2500 nm 范围内显示出典型的 Tb 吸收。YIG 和 Bi _0.9 Tb _2.1 Fe ₅ O ₁₂晶体的特定法拉第旋转在 1550 nm 处为 185 (°)/cm 和 –1250 (°)/cm，与通过 LPE 方法生长的商业 RIG 晶体相当。目前的结果表明，flux-Bridgman 方法显示出生长大尺寸和高质量 RIG 磁光晶体的巨大潜力。