Calcium-aluminate glass for use as n<1 hollow waveguides in the delivery of CO2 laser energy

Abstract

Calcium-aluminate glass has been studied as a possible candidate for use as an n < 1 hollow waveguide material at CO2 laser wavelengths. We have measured the optical constants, n and k, for calcium-aluminate glasses containing differing amounts of SiO2. Glasses with the lowest silica content have the n < 1 region centered near 10.6 μm, and, therefore, these are the best glass compositions for fabrication into attenuated total reflectance-type hollow waveguides. Our calculations of the attenuation coefficient for a hollow glass waveguide give a loss less than 0.5 dB/m at 10.6 μm. Applications of this technology include the use of hollow calcium-aluminate glass waveguides for CO2 laser power delivery in surgery and industrial cutting and welding.