BENDING LOSSES AND BEAM PROFILES OF ZINC SELENIDE-COATED SILVER WAVE-GUIDES FOR CARBON-DIOXIDE LASER-LIGHT

Circular hollow waveguides with an interior silver layer and an inner coating of zinc selenide are fabricated. The fabrication process for rf sputtering of zinc-selenide and silver, electroplating of nickel, and etching of a polyimide mandrel is described in detail. As a result of the measurements of transmission losses, the waveguides show a remarkably low-loss property when they are bent. Further, output beam profiles of the straight and the bent waveguide are investigated, and it is shown that the waveguide with a smaller diameter exhibits a well-shaped beam profile without sacrificing the low-loss property.