USE OF A YAG-ER LASER WITH A CHALCOGENIDE FIBER WAVE-GUIDE IN LASER-SURGERY

The damage thresholds of bulk high-purity chalcogenide glass samples and of fibre waveguides made from them were determined for YAG:Er laser radiation (lambda = 2.94 mu m). A cumulative effect was observed: the optical strength decreased during repetitive application of laser pulses and this was true both of the bulk samples and of the fibre waveguides. A correlation between the damage threshold and the concentration of heterophase inclusions was established experimentally. When the inclusion concentration was less than 10(4) cm(-3), the damage threshold exceeded 1 kJ/cm(2) for single pulses and was approximately half that in the pulse-periodic regime. The measured energy density of the lambda = 2.94 mu m radiation, needed for efficient cutting of the biotissues of the crystalline lens of the human eye, amounted to 50 J/cm(2). The feasibility of constructing a scalpel with an Er laser and transmission of its high-power radiation (up to 1 kJ/cm(2)) along a chalcogenide fibre waveguide was demonstrated in principle.