Fabrication and performance optimization of novel (Tb0.9975R0.0025)3Sc2Al3O12 (R= Pr, Ho, Dy, Eu) magneto-optical transparent ceramics

Abstract

Magneto-optical materials with high Verdet constants at high extinction ratios are desirable for the Faraday isolators. However, current terbium-based crystals have encountered several issues, such as low Verdet constants (TGG crystals), difficult growth (TSAG crystals), and low utilization of raw materials, which limit the development of the Faraday isolators. Here, R0.0025TSAG (R= Pr, Ho, Dy, Eu) transparent ceramics are prepared. The ceramics exhibit high optical transparency above 74.0% in the 525–1565 nm range and a high relative density of 98.9%. In particular, the transmittance of R0.0025TSAG ceramics at 1064 nm is approximately 81.6%, 81.6%, 79.8%, and 80.6%, respectively. The Verdet constants of R0.0025TSAG ceramics at the measurement wavelength are greater than those of the TSAG ceramic. The compelling magneto-optical performance of the Dy0.0025TSAG ceramic includes a high Verdet constant of 161.8 ± 3 rad·m−1·T−1 at 635 nm. The Verdet constant of the Dy0.0025TSAG ceramic is still superior to that of TSAG ceramic in the same temperature range. The extinction ratios of the R0.0025TSAG (R= Pr, Ho, Dy) ceramics exceed 40 dB. The figure of merit points out the superior characteristics of R0.0025TSAG ceramics. Moreover, R0.0025TSAG (R= Pr, Ho, Dy) ceramics with a thickness above the centimeter level are successfully prepared. This work indicates that the Dy0.0025TSAG ceramic can promote the miniaturization of magneto-optical isolators and can be applied in high-power lasers.