Abstract

The key to an effective laser material evaluation program is a ready supply of crystals at a reasonable cost. For most studies a crystal rod size of 1-mm diameter and 10-mm length is sufficient. More important for material optimization is the number of crystals with different dopant concentrations. Bulk growth techniques would not be appropriate for this task. This paper presents the laser-heated pedestal growth technique as a fast and cost-effective way to grow small laser crystals. Rare earth doped garnets of good crystal quality are now routinely grown at our facility. Lifetime measurements showed good agreement with those of bulk crystals. Tm:YAG is one of the dopant/host combinations studied as a function of dopant concentration. At high thulium concentration, excitation in metastable ³F₄ ions can migrate over a large number of sites in the lattice and be quenched by impurities and defects in the crystal. Only a slight decrease in lifetime was observed in our crystals, same as for bulk grown crystals. This attests to the crystal quality and demonstrates the viability of this growth technique for material optimization and comprehensive study of energy pathways in laser crystals.

© 1989 Optical Society of America