Evaluating Thermo-Optical Properties of (Tb0.6Y0.4)3Al5O12 Magneto-Optical Ceramics for High-Power Laser Applications

Mixed (Tb0.6Y0.4)3Al5O12 (TYAG) ceramics with superior optical properties were successfully produced using a solid-state reactive sintering method and subsequent hot isostatic pressing (HIP) treatment. We examined the optical (transmittance and Verdet constant) and thermal-optical characteristics of the ceramics. The prepared TYAG ceramics had an average grain size of ~35 μm and a high in-line transmittance of 83.8@1064 nm. The resulting TYAG ceramics exhibited a Verdet constant of 34 rad/T/m at 1064 nm, which is slightly lower than that of commercial Tb3Ga5O12 crystals (36–40 rad/T/m). We demonstrated that a Faraday isolator based on the TYAG ceramics achieved an isolation ratio of 30 dB with a laser power of 600 W. Using a higher magnetic field of 2.5 T, it is estimated that laser power could increase up to 850 W, without the need for additional adjustments or orientation selection. With its exceptional optical quality and maximum operating power, TYAG transparent ceramics are a promising candidate for use in high-power Faraday isolators.