Properties and fabrication of crystalline fluoride materials for high power laser applications

Fabrication and properties of two fluoride crystal families which exhibit a natural rare earth site are described. Two crystalline fluorides, yttrium lithium fluoride, or LiYF4, and potassium yttrium fluoride, or KY3F10, have specific desirable properties for high power laser applications. Advanced material processing techniques were developed, including feed purification and crystal growth techniques, to fabricate fluoride crystals exhibiting excellent transmission, low scattering, and high resistance to laser damage. Crystal growth developments scaled the crystal growth of YLF to 100 mm diameter. Growth parameters were optimized to maintain proper crystal-melt interface to minimize the formation of defects. Technical problems were addressed in scaling the crystal growth of YLF to 40 cm diameter.