TAG magneto-optic ceramics and its application in high power optical isolators

Abstract

Terbium aluminum garnet(TAG) is an excellent magneto-optic(MO) material with high Verdet constant and high thermal conductivity, but it is difficult to grow large-size TAG crystal due to its incongruent melting characteristic. By fabricating TAG ceramics through solid-state sintering, this problem can be effectively circumvented. In this paper, the recent research progress on the optimization of the optical quality and MO properties of TAG ceramics were reviewed. The high power performance of TAG ceramics, including their thermal depolarization effect, MO figure of merit, etc., were summarized and compared in details. Except for scattering loss, the key role of the microstructure of TAG ceramics, especially for the uniformity and size distribution of grains, in the generation of thermal depolarization was revealed and discussed, which provides a guideline to the fabrication of TAG ceramic with high MO figure of merit.