The Study On The Crystal Growth And Properties Of The Ce～(4+) And Zr～(4+) Doped KTP Crystal

In this paper, efforts have been made to study the crystal growth, crystal morphology and integrity, crystal structure and relevant properties of Zr4+-doped and Ce4+-doped KTP crystal. More than twenty doped KTP crystals with different dopant and different doping concentration were grown by flux method. The cell parameters of the crystals were determined by x-ray single crystal diffractometer and change little in comparison with the pure one. Also, the Laue spot of the doped KTP crystals was simulated and is same to the pure one. All Zr4+doped and Ce4+-doped KTP crystals comprise the same faces as the pure one. But all the doping modifies the crystal morphology, and a-axis size of the doped crystal turns thinner, especially fOr .the Zr4+-doped KTP crystals. The Zri+-doped KTP crystal is plate-like and the Morphology of Ce4+-doped is more like the pure KTP crystal. Some macroscopical defects in doped KTP crystals have been observed directly or by optical microscope, such as inclusions, cracks and growth steps. Meantime some microscopical defects have been found by White-beam Synchrotron Radiation topography, such as the growth sector boundary and growth stripes. Thus, the integrity of the crystals was destroyed. There is more defects density in Zr4+-doped KTP crystals than in Ce4+- doped KTP crystals, so the integrity of Ce4+-doped KTP crystals is better than Zr4+-doped KTP crystals. The distribution coefficients of the doping ions in the growth system have been calculated after the measurement of the dopant concentration in crystals by ICP. Because of the larger ion radius than Ti4+, Ce4+is hard to enter the inner structure for substituting Ti4+ and the distribution coefficient is rather low. Zr4+, which is almost similar to Ti4+ in size, is easy to enter the inner structure and substitute Ti4+., thus obtaining a large distribution coefficient. The results show that the distribution coefficient decreases with the increase of the doping concentration.. The transmission curve, doubling effect and a-axis conductivity were tested by relevant methods. The results show: Ce4+ doping can improve the transmission of KTP crystal while Zr4+ doping have no influence on it; Ce4+and/ or Zr4+doping can increase the doubling effect and Ce4+ doping has more influence than Zr4+ doping on it; Zr4+ doping can make the a-axis conductivity decrease and Ce4+ doping has no any influence on it.