METHOD OF YTTRIUM-ALUMINIUM GARNET'S MOSAIC-LESS MONOCRYSTALS PREPARATION WITH FLAT PHASE BOUNDARY

摘要

A method of growing yttrium-aluminium garnet mosaic-less monocrystals with flat phase boundary The invention concerns a method of growing yttrium-aluminium garnet mosaic-less monocrystals with flat phase boundary, so the cylindrical parts of the crystal have high optical homogeneity and are suitable for processing into dimensionally complex optical products, for example laser rods of large diameter or laser plates. Yttrium-aluminium garnet mosaic-less monocrystals are grown by melting from nucleus melt and flat phase boundary between the melt and crystal is achieved whereby the monocrystals are drawn in a protective atmosphere containing 50 to 98 % volume argon and/or helium and 2 to 50 % volume and the humidity of the protective atmosphere falls during the initial period of growth, i.e. before achieving a crystal length corresponding to 100 to 300 % of its greatest diameter, from 3,400 to 1,000 ppm volume to 600 to 100 ppm volume of water vapour. It is also suitable to supplement this working procedure whereby, during reduction of the humidity of the atmosphere, the content of nitrogen is modified to 0.005 to 5 % by volume.