Method and apparatus for growth of large size nonlinear optical crystal by copple and inoculating crystal

Abstract

The invention relates to a method for growing a large size non-linear optic crystal through the linkage of a crucible and a seed crystal. In the growth process of growing the non-linear optic crystal through a molten salt method, the seed crystal is placed in a fused mass or on the surface of the fused mass; and the seed crystal and the crucible rotate synchronously and oppositely according to a certain rotation period. A device comprises a crystal growth device and a controller capable of driving the seed crystal and the crucible to rotate synchronously and oppositely according to the certain rotation period. The synchronous and contrarotational rotation period comprises the following steps: rotating acceleratively, rotating at a uniform speed, rotating deceleratively and stopping rotation in turn in a first direction; and then rotating acceleratively, rotating at a uniform speed, rotating deceleratively and stopping rotation in turn in a second direction opposite to the first direction. The synchronous and contrarotational rotation of the seed crystal and the crucible with an adjustable rotating speed facilitates the impurity removal in an early growth period of the seed crystal, grows a single crystal with a regular shape, and reduces or even eliminates the risk of the breaking of the seed crystal caused by an oversize moment resulting from the overweight of the seed crystal.

Description

technical field [0001] The invention relates to the technical field of crystal growth, in particular to a method and device for growing a large-size nonlinear optical crystal in conjunction with a crucible and a seed crystal. Background technique [0002] Crystal growth includes a series of processes, such as the formation process of crystal growth units, the transport process of crystal growth, and the dynamic process of crystal growth interface, among which the transport process is an important link. The crystal growth process is actually a transport process of heat, mass and momentum. Crystal growth is a process of spatial discontinuity and non-uniformity, and crystallization is only at the growth interface. [0003] The effect of stirring on the growth rate and quality of crystals must be fully realized. When growing a crystal in a melt or solution, a forced convection will be generated by the rotation of the crystal or the rotation of the crucible. At this time, the tr...

AI Technical Summary

Problems solved by technology

[0004] The traditional methods of growing nonlinear optical crystals are mostly: in the process of growing nonlinear optical crystals, either using a separate rotating seed crystal to grow nonlinear optical crystals (ACRT technology); or using a separate rotating crucible to grow For nonlinear optical crystals, the disadvantages of the two methods are: in the early stage of growth, impurities cannot be well removed at the solid-liquid interface, and it is easy to form wrapping defects and cause defects to extend inside the crystal.

Since each crystal has a fixed shape and is not completely symmetrical to the seed crystal, a large torque will be formed at the seed crystal when the crystal rotates. If the crystal weight is too large, the seed crystal will be twisted and the crystal will fall off. Large size crystals are disadvantageous

The reason why the traditional dissolved salt method and ACRT technology cannot be used simultaneously in practical applications is that the movement of the seed crystal and the crucible cannot be changed synchronously, that is, the crystal and the crucible will rotate in the same direction due to the accumulation of time errors.

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