A commercial model of an optically pumped, pulsed,2-micron-wavelength, solid-state laser will be modified and tested for Q-switched performance. At least two different types of laser crystals- Tm:Cr:YAG and Ho:Tm:Cr:YAG-will be used to investigate the differences in pulse length and energy extraction efficiencies for the two- and threestep energy transfer mechanisms responsible for laser action in these crystals. The laser will then be coupled to a high-infrared-transmission, fused-silica fiber and the whole system used to study laser tissue interactions in the eye. Sectioning of vitreous membranes, lens fragmentation, and glaucoma-filtering procedures will be explored as a function of laser fluences and wavelengths. It is hoped that differences in tissue interaction, if any, can be observed that are due to the varying absorption coefficients of the 2.01-llm Tm wavelength and the 2.1 2-llm Ho wavelength as determined by their relative positions on the shoulder of the 1.94-llm water absorption peak. Commercial potential of the device will be assessed based on the comparison to existing modalities, e.g., CUSA and diamond knife.Awardee's statement ofthe potential commercial applications of the research: Favorable results would lead to a compact, reliable medical laser that by allowing a Q-switched or normal-mode operation, would have the capability of high-precision and large-volume ablation as well as coagulation. The system would find applications in ophthalmic and microsurgical fields as well as in angioplasty and lithotripsy.National Eye Institute (NEI)
