Optical properties of improved Tb2Hf2O7 pyrochlore ceramics.

Ultra-high density and optical grade Tb 2 Hf 2 O 7 (THO) pyrochlore ceramics was successfully synthesized by reactive sintering of Tb 4 O 7 and HfO 2 and successive HIP treatment. Residual pores were not observed in the material, and it was optically isotropic in transmission polarization observation. Its optical loss was considerably lower than 0.1%/cm. Optical homogeneity was significantly improved by additional annealing in hydrogen at 1700 °C after the HIP treatment. A very good laser beam profile was observed via the THO ceramics. Verdet constant, insertion loss and extinction ratio of this ceramics at 1064 nm were 50 radT−1m−1, 0.03 dB and 38 dB, respectively, better than that of the commercial TGG single crystal. • Optically homogeneous pyrochlore Tb 2 Hf 2 O 7 (THO) ceramics with low optical loss (0.1%/cm) was successfully produced for Faraday rotator materials by a solid-state reactive sintering and HIP process followed by annealing in hydrogen at high temperature. • Residual pores which cause Mie scattering were not observed in the THO ceramics. • Verdet constant, insertion loss, and extinction ratio of the THO ceramics exceeded the characteristics of commercially available TGG single crystals. [ABSTRACT FROM AUTHOR]