Punctate Seeded Growth Of Kdp Crystal Defects

KDP crystal is a type of excellent electro-optical non-linear optical materials, which is widely applied in the field such as laser radiation, electro-optical modulation and optical rapid switch etc. Thus it is a good choice for the artificial percolating laser system. Because of its spreading usage in these fields, a high quality in KDP crystal is being required to ensure its effectiveness and laser damage threshold.It is usually unavoidable for the emergence of several kinds of defect in KDP crystals, such as stripes, dislocations and scatters, so that these KDP crystals are improbable topractically use. In that case, the defects in KDP crystals turn extremely important to study completely. Now that the formation of the defects is complex, it appears quite fundamental for us to find out the mechanism of that, which is meaningful to enhance the quality of KDP crystals. It is an effective method to decrease the defects by changing the growth conditions, after which investigations can be done to validate the expectations so as to open out the mechanism of the formation of those defects. Under this guide, crystals with different qualities have been got in different conditions of the pH value or the temperature descent. In this experiment, the growth morphology differs, the pH value changed and the growth rate differs, the temperature descent changed. Also, dislocations are investigated under an optical microscope. The results show that the dislocation types will be less when a point seed used in the growth process than when a slice seed used and this validates the effectiveness of the point seed in reducing the dislocation types in KDP crystals. An in situ experimental observation of the growth steps is designed, an optical microscope and a triced up bottle used. The in situ photos demonstrate the moving process of the growth steps by the screw dislocations. The observation gives a direct demonstration of the screw dislocation growth system. Scatters are investigated under the ultra-microscopy. The results validate the relation between the scatters and the growth condition such as pH value and temperature descent. An analysis is done to explain the relation between dislocations and scatters in the KDP crystal originating from a point seed. And the relation is validated under the ultra-microscopy.