Lu3Al5O12 single crystals codoped with thulium and holmium were successfully grown by the Czochralski technique. A highly strained central core region caused by facet formation on the growth interface was observed. The distribution of birefrignence in the radial direction except in the core region was of the order of 10(-7). The segregation coefficients of the dopants in these crystals were estimated to be 0.87 and 0.73, respectively. The measured thermal expansion coefficient of Tm,Ho: Lu3Al5O12 single crystals was 8.48 x 10(-6) K-1. Laser performance of Tm,Ho: LU3Al5O12 was measured. (C) 2002 Elsevier Science B.V. All rights reserved.