Fabrication and characterization of a gadolinium-doped terbium gallium garnet crystal with an enhanced Verdet constant

Magneto-optical materials based on Tb₃Ga₅O₁₂ (TGG) crystals offer promising opportunities when used in modern Faraday isolators (FIs). Gadolinium (Gd)-doped TGG (Gd:TGG) crystals with high transmittance were prepared using the Czochralski (Cz) method. The as-prepared crystal presented a high optical transmittance of up to 80.0% in the range from 520 nm to 1520 nm. The Verdet constants of the as-grown crystal at 405.0, 533.0, 632.0, and 1064.0 nm were -583.0, -230.1, -150.3, and -50.3 rad m^-1 T^-1, respectively. The measured value at 1064 nm was about 1.3 times stronger than that of TGG. Thus, it could minimize the strength of the magnet of Faraday rotators. These excellent characteristics make Gd:TGG single crystal an attractive magneto-optical material.