Bending losses and beam profiles of zinc selenide-coated silver waveguides 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.