Crystal growth of laser oxides in the vertical Bridgman configuration

Abstract

In the middle of the 1970's, solid state lasers were based mainly on ruby (Al 2O 3-Cr 3+), Nd 3+-doped yttrium aluminum garnet (Y 3Al 5O 12-Nd 3+) and Nd 3+-glass. Several other host crystals and laser ions were already known as possessing high potential for generation of stimulated emission in different spectral regions however, problems existed in the crystal growth of high-quality materials. The vertical Bridgman technique was among those widely practiced both in research of high melting laser oxides and in analysis of crystal growth characteristics providing optical quality material. This paper reviews the major results obtained during the last years in the growth of various crystalline oxides in the vertical Bridgman configuration with emphasis on rare-earth aluminum garnets and orthorhombic perovskites. Radiant heat exchange, gas bubble initiated solute convective transport and other physical phenomena are considered with respect to their effect upon the solid-liquid interface shape, facet formation and impurity incorporation. The ability of oxide melts to undergo supercooling has been considered, primarily in the context of melt property studies and development of a self-seeding process applicable to crystal growth of unstable end-member rhombic aluminates of the lanthanide group.