Heavily Tm-doped (5-20at%) GdVO4 single crystals were successfully grown by the floating zone method. All the grown crystals had no cracks and no inclusions for any dopant concentration. Low-angle grain boundary-free crystals were easily grown along the [1 1 0] direction whereas the crystals grown along the [0 0 1] direction comprised a few low-angle grain boundaries. The formation of bubble inclusions was effectively suppressed by optimizing growth rates and rotation rates. The absorption coefficient around 800 nm was large enough for pumping with a laser diode of 808 rim, which is conventionally used for Nd lasers. Intensive emission was observed even above 1950 nm where the self-absorption could be neglected. The fluorescence decay time decreased from 2.1 to 0.5 ms with increasing Tm concentration but is long enough for laser oscillation. (C) 2004 Elsevier B.V. All rights reserved.