Magneto-optical Dy₂O₃ ceramics with optical grade

Optical grade Dy₂O₃ ceramics was successfully produced by adding a small amount of ZrO₂ as a sintering aid and hot isostatic pressing treatment at 1500^∘C after pre-sintering at 1550^∘C. No residual pores, grain boundary phases, or second phases were detected inside the transparent ceramics. Since birefringence was not observed under the polarizer, the produced Dy₂O₃ ceramics is an optically isotropic body. There was almost no beam distortion during the laser irradiation test, and the optical loss was extremely small (<0.1%/cm). The Verdet constant was 422radT^-1m^-1 at a wavelength of 633 nm, and the extinction ratio was 34 dB.