The high optical quality Tm: YAG single crystals with dopant concentrations of 2, 4, 8 at % Tm3+ ions have been grown by the Czochralski (CZ) method. The segregation coefficients of Tm3+ ions in CZ-grown 2, 4, 8 at % doped Tm: YAG crystals deter-mined by ICP-AES method are equal to 0.93, 1,04, 1.10, respectively. The absorption spectra in the range of 190-900 nm and the IR absorption spectra in the range of 1000-4500 cm(-1) of the Tm: YAG crystals were also measured at room temperature. The results indicate that Tm: YAG is favorable for laser diode-pumped system, and air annealing can improve the quality of the Tm: YAG crystal. (C) 2004 Elsevier B.V. All rights reserved.