Abstract
We report the fabrication and the characterization of large KTP crystals. The crystals were grown for approximately forty days by a top-seeded solution method using a K6P4O3 flux. The size was 32×42×87mm3 in a×b×c axes. A very high level of structural perfection was observed by synchrotron x-ray topography. But large changes of the refractive index were observed between growth sectors and successive changes of the index from the intial part of the growth near the seed to the final part were observed inside individual growth sectors. This may explain the different values of the phase matching angle reported in many laboratories.
