GROWTH OF BROAD LINEWIDTH RUBY CRYSTALS
Abstract
Progress has been achieved in perfecting the techniques for the growth of ruby from flux and broadening the fluorescent linewidth by Ga additions. It has been demonstrated that large flux free ruby crystals suitable for fabrication into laser rods can be produced by spontaneous nucleation from slowly cooled molten salts. By lowering the pedestal supporting an 8 inch x 8 inch crucible until a 200C gradient is obtained, and slowly cooling a PbF2 melt at 1.5C per hour, large ruby plates up to 3/8 inches thick and 2 inches in maximum dimensions have been grown. Attempts to grow larger crystals by growth on ruby seeds were not successful, but it was established that crystals can be grown free from chromium content variation by using ruby nutrient and growing crystals in a temperature gradient under steady state conditions. Solubility of Al2O3 in PbF2 has been measured and the effect of Cr and Ga on the solubility has been determined. Chemical analysis of the crystals shows a concentration gradient exists for Cr but not for Ga. Line broadening was achieved in ruby crystals both by the deliberate addition of Ga, and by the substitution of 0(2-) by F(-) during crystal growth. Broadening in excess of 10/cm was obtained due to a combination of these factors. Two rods cut from these crystals lased at 2000 and 1200 joules respectively in a 3 inch long laser head at 200K.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 30, 1964
- Accession Number
- AD0615557