Nanomaterials @ Interfaces Research Group

High power Nd: YAG laser rods may easily exceed their fracture strength as a result of thermally induced tensile stress. Strengthening of such rods is achievable at elevated temperatures by wet chemical etching in concentrated orthophosphoric acid or in a mixture of phosphoric and sulfuric acids. In the present study, the etching rates of Nd:YAG in both etchants were determined as a function of temperature. The calibration curves thus obtained enabled the controlled removal of the outer "damaged" layer of lasing elements. Four-point flexure strength measurements were performed on deep etched and on non-etched YAG slabs. The measurements showed a 3.5 fold increase in the strength of the etched slabs. Weibull analysis treatment was carried out on the basis of our fracture data.