INVESTIGATION OF OPTICAL INHOMOGENEITIES IN KTIOPO4 (KTP) SINGLE-CRYSTALS GROWN FROM HIGH-TEMPERATURE TUNGSTEN-CONTAINING SOLUTIONS

Striations and sectors in the KTP crystals grown from high-temperature tungsten-containing solutions were optically observed. Inhomogeneous distribution of tungsten across the striae and the boundary between th e sectors was revealed in an SEM by electron probe microanalysis using a multiple linescan method. It was concluded that the striations in t he crystals result from the unequal incorporation of tungsten during t he growth process, caused by temperature fluctuations. Experiments to create induced striations in KTP crystals were performed in order to e valuate the temperature fluctuation amplitude below which no striae ar e optically distinguished. It was established that the striae are alre ady scarcely visible when the fluctuation amplitude is 0.12-degrees-C.