Gas bubbles in shaped sapphire

Facet Appearance on the Lateral Face of Sapphire Single-Crystal Fibers during LHPG Growth

“…The probability of bubbles formation depends on a number of different factors. In some experiments voids and bubbles capture was observed at lower pulling rate [27,28], but our experience demonstrated that it is possible to grow high optical quality sapphire fibers even at 2 cm/min pulling rate with the use of a high-quality single crystal source rod. Therefore, we chose the pulling speeds at which high optical quality was ensured.…”

Growth and spectroscopic properties of Ti-doped sapphire single-crystal fibers

“…So the bubbles will accumulate at crystallization interface and are incorporated between the facets in elongated form [26]. The gases contained in the bubbles come from the chemical reactions taking place in the growth chamber [27]. In our experiment, due to iridium crucible and high purity argon gas used, the most possible of gas origin is the dissociation reaction of Al 2 O 3 .…”

The Role of Marangoni Convection in Crystal Growth

“…It has been reported that the gaseous inclusions and their locations in the rod sapphire crystals [90,91] or the dopant distributions in single crystal fibers of Nd:YAG and Nd:LiNbO 3 [92] were affected by the Marangoni flow in the melt meniscus. A seed crystal is put in contact with the melt meniscus and pulled up so that the single crystal with a cross-section controlled by the die geometry can grow.…”