Properties of TAG ceramics at room and cryogenic temperatures and performance estimations as a Faraday isolator

We investigated material properties of terbium aluminum garnet (TAG) ceramics and its characteristics as a material for a Faraday isolator for high-average power lasers. We measured the transmittance, absorption coefficient, and temperature dependencies of Verdet constant and thermal conductivity. Consequently, our model analysis shows that TAG ceramic isolators can be operated over 3 kW average laser power at a 30 dB isolation ratio. The power limit becomes higher if a gas cooling scheme is applied.