method for breeding of rare earths doped orthosilikaten (ln2 - xrexsio5).

摘要

The invention is a technique for the growth of single crystals of rare earth doped rare-earth orthosilicate crystals which may be used as the laser medium in solid-state non-semiconductor lasers. This type of laser has applications in electronics, communications, aerospace systems, and manufacturing technology where high optical output lasers are utilized. Of particular interest is the Y2-xNdxSiO5 crystal, with x being up to 0.3, which may be efficiently pumped by a semiconductor laser, solid state non-semiconductor laser, a flashlamp or some other source of light radiation, and has been found to be operable at very high optical output. The rare-earth orthosilicate crystals are grown in accordance with this invention by a Czochralski technique from a molten mixture of constituent oxides in an inert atmosphere containing oxygen. Inclusion of oxygen in the inert atmosphere in concentration of from about 300 to about 9,000 PPM of oxygen resulted in substantial reduction in the density of light scattering defect sites and, thus, in substantial increase in the optical energy which may be applied to the crystal without causing substantial damage to the crystal in comparison to the crystals grown in an inert atmosphere containing less than 300 PPM, such as 200 PPM and less, of oxygen. Absorption of energy from the high optical flux present during the laser operation at these defect sites results in farther degradation of the laser crystal. Through selection of the O2 concentration in the atmosphere in which the crystal growth is performed, the density of defects which produce light scattering has been significantly reduced. By application of the growth atmosphere composition control, optical damage thresholds have been increased by more than an order of magnitude.