Recent advances of rare earth iron garnet magneto-optical single crystals

R₃Fe₅O₁₂ (RIG) crystals are the most desirable elements for magneto-optical isolators in the near-infrared (NIR) to mid-infrared (MIR) region, with ever-growing demands for optical fiber communication and high-power laser system. Now, this system is the only commercialized Faraday rotator for optical isolators in 5G wireless communications. However, the growth of high-quality bulk RIG single crystals has been a big challenge for a long time, due to the typical incongruent melting characteristic and complex phase relationships. This work comprehensively summarizes the recent advances for the growth of RIG single crystals, including the proper choice of flux and innovative strategies on several growth techniques, like the flux-Bridgman, edge-defined film-fed growth (EFG) and top seeded solution growth (TSSG), etc. Effective modulation on the optical and magneto-optical performance is highlighted. Some ongoing perspectives are also proposed and discussed. It is anticipated that this work will provide deeper insight into the exploration of high-performance magneto-optical crystals for potential applications in NIR-MIR wavelength.