Evaluation of sapphire fibers for laser medical applications

Transmission measurements have been made to evaluate the optical properties of single-crystal sapphire fibers and to assess the utility of these fibers for medical applications. Measurements of some of the first fibers drawn show transmission near the Fresnel limit in the visible with expectedly higher scattering losses in the ultraviolet. Data also suggests the presence of color centers, and increased transmission has been observed after annealing at temperatures to 1200 K. Preliminary measurements of optical breakdown strength suggest a limit of about 1 kJ/cm/sup 2/. >