Large size 0.62PMN-0.38PT single crystals with high optical quality have been grown by a modified Bridgman technique. X-ray diffraction shows they have tetragonal phase and are free of pyrochlore phase. The melting point and thermal stability of the as-grown crystals were measured using simultaneous thermo-gravimetric analysis and differential thermal analysis. The optical transmission spectra from 0.3 to 11 mum of a <0 0 1>-cut 0.62PMN-0.38PT single crystal were studied at room temperature. The extinction ratio is also measured from 20degreesC to 70degreesC. The wide transparent region (from 0.45 to 5.5 mum) and high optical transmittance (about 70%) indicate that the crystals can be used in a very wide wavelength region. The high extinction ratio, which is independent of temperature is an important property for optical device application. Some discussions about the oxygen-octahedra structure that determines the basic energy level of the crystals are also presented in this paper. (C) 2003 Elsevier B.V. All rights reserved.