A STUDY ON STRATIFICATION OF CONCENTRATION IN CRYSTAL-GROWTH OF ALPHA-LIIO3 BY HOLOGRAPHIC-INTERFEROMETRY

A new thermoplastic-photoconductor laser holographic recording system has been used for real-time and in situ observation of alpha-LiIO3 cry stal growth. The influence of crystallization-driven convection on the concentration stratification in solution has been studied under gravi ty field. It is found that the stratification is closely related to th e seed orientation of alpha-LiIO3 crystal. When the optical axis of cr ystal seed C is parallel to the gravity vector g, the velocity of the concentration stratification is two times larger than that in the case of C perpendicular-to g. It needs 40 h for the crystalline system of alpha-LiIO3 to reach stable concentration distribution (expressed as t au) at 47.6-degrees-C. The time tau is not sensitive to the seed orien tation. Our results provide valuable data for designing the crystal gr owth experiments ia space.